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LABORATORY

OF ORNITHOLOGY
LIBRARY

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CORNELL UNIVERSITY LIBRARY

Cornell University

The original of this book is in
the Cornell University Library.

There are no known copyright restrictions in
the United States on the use of the text.

http://www.archive.org/details/cu31924022546406

LABORATORY OF ORNITHOLOGY ©
CORNELL UNIVERSITY ~~;
ITHACA, NEW YORK -

CONCEALING-COLORATION

IN THE

ANIMAL KINGDOM

pay Gy/ “ Varguuce Ce lee ao
Jileg 1/96 /°

EXPLANATION OF PLATE I

yo,

PEACOCK IN THE WOODS.

Painted by Abbott H. Thayer, assisted by Richard S. Meryman

The Peacock’s splendor i is the effect of a marvellous combination of ‘obliterative’ designs,

in forest-colors and patterns. From the golden-green of the forest’s sunlight, through all its © ;

tints of violet-glossed leaves in shadow, and its coppery glimpses of sunlit bark or earth, all
imaginable forest-tones are to be found in this bird’s costume; and Shey ‘melt’ him into the
scene to, a degree past all human analysis.

Up in the trees, seen from below, his neck is at its pine” ‘and ‘when sunlit, perfectly
represents blue sky geen through the leaves. Looked. down on, in the bottom shades ‘of the

jungle, it has rich green sheens which ‘melt’ it into the surrounding foliage. His back, in

all lights, represents golden- green foliage, and his wings picture tree-bark, rock, ‘éte., in

sunlight and in shadow. His green-blue head is equipped with a crest which greatly helps

it against revealing its contour when it moves. Accompanying its every motion, this crest

is, as it were, a bit of background moving with it. The bare, white cheek-patch, on the’

other hand, ‘cuts a hole,’ like a lighted foliage-vista, in the bird’s face. The tail, when

ce -spread—or even when shut—‘thingles’ in a thousand ways with its jungle surroundings. The

ocelli, guaranteed by their forest-scenery colors to: vanish into the background at a short
distance, have one peculiarly fantastic use. Smallest and dimmest near the body, and growing
bigger and brighter in even progression toward the circumference of the tail, they. inevitably

' lead the eye away from the bird,’ till it finds itself straying amid the foley beyond the tail’s

evanescent border.
The apread tail looks also very much like .asbrub bearing some kind of fruit or flower.

Its coppery ground-color (in a front view) represents ‘perfectly that of the bare. ground and
tree-trunks seen between ‘the leaves. The very positiveness of the design in such details as
an ocellus, works to conceal the wearer, on the principle explained | in the Introduction by
the quotation from Stevenson. The forest i is so full of highly : individualized vegetable forms,
and of many-colored spots and streaks made by ‘their. confused outlines, that the predator’s
eye, watching mainly for motion, doubtless gives. but slight attention to any of them, or to
anything that looks like one of them. In addition to all this, every changed point of view on
the beholder’s part makes all the bird’s details assume new colors and new correlations to
each other and to the scene.—A. H. T.

CONCEALING-COLORATION

IN THE

ANIMAL KINGDOM

An Exposition of the Laws of Disguise
Through Color and Pattern:
Being a Summary of

ABBOTT H. THAYER’S
DISCOVERIES

By ~

GERALD H. THAYER

WITH AN INTRODUCTORY ESSAY BY
A. H. THAYER

ILLUSTRATED BY

ABBOTT H. THAYER GERALD H. THAYER
RICHARD S. MERYMAN AND OTHERS
AND WITH PHOTOGRAPHS

NEW YORK
THE MACMILLAN CO.

1909

LABORATORY OF ORNITHOLOGY

CORNELL UNIVERSITY

ITHACA, NEW YORK - ae
arr sone te RE

SISCOG

THE TROW PRESS, NEW YORK

LITHOGRAPHS AND HALF-TONES BY
A. HOEN & CO., BALTIMORE

PREFACE

HE first publication of Abbott H. Thayer’s discovery of ‘‘The law which
underlies Protective Coloration” was in the American journal of
ornithology, The Auk, in April, 1896. This was followed in the next issue
of the same magazine by a supplementary article, “Further remarks
on the law which underlies Protective Coloration.” The two essays were
illustrated by diagrams, and photographs, chiefly of dead birds. They were
republished together by the Smithsonian Institution in its “Yearbook” for
1898. A condensed revision of their text, with an introduction by Prof.
Edward B. Poulton, was published in the English magazine, Nature, in 1902.
Mr. Thayer has also given practical demonstrations of his discovery before
various congresses of naturalists, both in the United States and in Europe,
and has placed models illustrating it in several European museums (Oxford,
Cambridge, and South Kensington, England, and Florence, Italy). Thus
this newly discovered basal principle of Protective Coloration has been brought
to the attention of most of the world’s best naturalists, and the bare rudiments
of the matter have become to some extent current knowledge among them,—
though comparatively few of them have yet given proof that they perceive
how completely this and certain parallel subsequent disclosures have revo-
lutionized the study of Protective Coloration, and supplanted former theories.
In the last few years, however, this discovery has been rapidly gaining recog-
nition, and mention has been made of it in many writings on Natural His-
tory, both popular and scientific, especially in England. Yet the subject is
still very far from receiving its destined full and universal appreciation by
nature students in general, and much of the current writing about the colors
of animals is worse than useless, inasmuch as it works for the retention of
antiquated delusions. Indeed, although the study of Protective Coloration
vii

is now generally acknowledged to be one of the most important branches of
zoological science, there still exists among the otherwise well informed a
complete ignorance and misconception of the main laws on which Pro-
tective Coloration is based.

The present book has been constructed for two main purposes: First, to
lay before the comparatively few naturalists and others who have duly appre-
ciated the original articles on the subject, the results of my father’s further
researches, with examples of the working of the newly revealed laws in many
branches of the animal kingdom; and second, to present the matter, both in
its simplest terms and variously elaborated, to a wider circle of readers. We
hope thus to clear the way to a more general understanding and more intelli-
gent study of the relations between animals’ costumes and their environments.
As the book stands, although it has a far wider scope than the previously
published articles, it must be considered merely a fragmentary introduction
to the huge and fascinating subject of Protective Coloration. Fundamental
principles are defined, and many examples are given, both by illustrations
and in the text, of the workings of these principles on actual animals; but
nothing like an exhaustive examination of the species of any branch of zoélogy
has been attempted.

For the most part, we do not draw hypothetical conclusions from facts;
but we reveal certain beautiful facts hitherto unknown; we disclose and ex-
plain the remarkable power of several naturally applied laws of optical illu-
sion—as these applications stand, by whatever causes produced, and as all
may see them. That is, we show and analyze the concealing-power of the
colors of animals as they exist to-day.

The illustrations are of particular importance, inasmuch as they include
what we believe to be the first scientific paintings ever published of animals
lighted as they actually are in Nature. This will be explained in detail later
on. The colored pictures have been painted either from mounted specimens,
as in the cases of the Grouse, the Wood Duck, and the Peacocks, or from
live captives, as in the cases of the Snake and all the Caterpillars. The pic-

viii

ture of the Grouse is a faithful copy of a specimen in a house-lighting arti-
ficially arranged to correspond to that which the live bird in the forest would
normally have; while the background was painted from photographs and
outdoor color sketches. The Snake is the joint production of A. H. Thayer,
Rockwell Kent, and G. H. Thayer. Three of the caterpillar pictures are
contributed by Louis A. Fuertes. The Bird of Paradise sketch is largely
the work of Mrs. A. H. Thayer; likewise most of the background in the rab-
bit picture, the diagrams of ‘ruptive’ coloration, and two or three black-and-
white diagrammatic drawings; besides a good deal of contributive work here
and there on other paintings; and an immense amount of miscellaneous labor,
invaluable advice and criticism, at almost every point.

The various photographs of live birds and mammals which appear in the
book have been gleaned from periodicals, or secured by special advertising.
We are particularly indebted for valuable pictures to the late Mr. Evan Lewis,
of Idaho Springs, Colo.; to Mr. Edward R. Warren, of Colorado Springs; to
Prof. F. A. Herrick, to Dr. T. S. Roberts, to Mr. George C. Embody, to Prof.
F. A. Lucas, and to Mr. C. Wm. Beebe; also to Mr. R. L. Ditmars, Curator of
Reptiles at the Bronx Zodlogical Park, New York, for the loan of a live Copper-
head snake, and other favors.

TABLE OF CONTENTS

Intropuction: sy Assotr H. Taaver. An Essay on the Psychological and other basic

Principles of the Subject - - - - «© - © «© «© © © 2 6
CHAPTER I
Outline of the book’s scope. ‘The Law which underlies Protective Coloration” introduced
andanalyzed. Poulton cited . . .« ~~ - -© «© © © © «© © |
CHAPTER II
Definition of terms. Obliterative Shading, pureandsimple - . . . . «. -

CHAPTER III

First principles of the use of markings with obliterative shading. ‘Picture-patterns’ . . .

CHAPTER IV

Picture-patterns, with obliterative shading, on birds. American Woodcock, and Snipe .

CHAPTER V
Picture-patterns on obliteratively-shaded birds, continued. Terrestrial Goatsuckers (Whip-poor-
willsete) 3 ws «S & 8 & @ = mo ce ko & S w « «& ~
CHAPTER VI
Picture-patterns on counter-shaded birds, continued. Forest Grouse, Owls, European Wood-
COCK Yop oth. la? co CAE Beladeds, Sel Jot) GP ce tee Se ee Ee ee
CHAPTER VII

Picture-patterns on counter-shaded birds, continued. Grass-patterns, heather-patterns. Spar-
rows, Waders, Ptarmigan, et. . - . . . . . . «2. 2...

CHAPTER VIII

Picture-patterns on counter-shaded birds, continued. Scansorial (Climbing) birds. Creepers,
Wrynecks, Woodpeckers, etc. 9. 7 ee ee

PAGE

CHAPTER IX

Picture-patterns on counter-shaded birds, continued. Shore-birds—Sandpipers, Plovers, etc.

Beech-sand-, pebble- and grass-picturing patterns. Generalizations and comparisons .
CHAPTER X

Picture-patterns on counter-shaded birds, continued. Reed-patterns, etc., of Bitterns. Other

Herons: water-colors and patterns . - . . . . . . 2. 2. «©
CHAPTER XI

Background-picturing on counter-shaded birds, continued. Marsh-birds: Water-birds (Galli-
nules, Rails, Ducks, etc.): detailed analysis of the Wood Duck’s consummate picture-
patterns: 2, Se ce Se! Ge ee RRO. Uc ee Se

CHAPTER XII
Background-picturing on counter-shaded birds, continued. Birds of the ocean. Sky- and
water-matching costumes. Gulls, Terns, Gannets, etc. re
CHAPTER XIII

Birds, etc. The inherent ‘obliterative’ power of markings. ‘Ruptive’ and ‘secant’ patterns,
ets ck | Bs ee et, Bg GO Rs a

CHAPTER XIV
Birds, etc. Special functions of markings. Circle-banded flight-feathers of Hawks and Owls.
Eye-masking patterns: eye-blazoning (?) patterns. The coloration of nestling birds -
CHAPTER XV
Birds. Masking of bill and feet for offensive purposes. The “pantaloons” of Hawks and Owls.
Gaudy bills and feet of Water-birds: red and yellow on many water-animals: Belt cited.
Jacanas, Anhingas, Herons, etc. Po ee
CHAFTER XVI

Birds, etc. The manifold obliterative power of iridescence. Changeable colors in general:
their part in water-picturing costumes, etc.; (Peacock), Jacamar, the “speculum” of
Ducks, ‘jewel-spots,” etc. 2. eee ee

CHAPTER XVII

Birds, etc. Appendages, and their part in ‘obliteration’: Resplendent Trogon: Pheasants and
their long, transversely-banded tails: consummate obliterative equipment of the Birds-of-
Paradise: ose Ge eG em

CHAPTER XVIIT

Birds: miscellany. ‘‘Mimicry” (vs. ‘obliteration’). The gorgeous head-gear of Humming-
birds not mimetic; its obliterative functions, etc. Sexual differences of costume a) J

xii

PAGE

100

CHAPTER XIX

Birds, concluded. The birds of tropical forests: brown ground-birds: gaudy perchers on tree-tops:
tree-top skulkers, etc.: Parrots and parrot-tails: Toucans: ruptive patterns, iridescence,
appendages: extreme color-contrasts: juxtaposition of complementary colors: green light:
Trogons and Tanagers: Chapman cited; etc. Winter birds of the snowy North: Blue
Jays, Magpies, Goshawks, Titmice, Woodpeckers, cone-birds, etc. White in birds’
costumes. Generalizations and comparisons 2 oe. Be a) Ge a Pet a

CHAPTER XX

Mammals. A running survey of the coloration of mammals, from bats to whales. Full oblitera-
tive shading almost universal among them. Exceptions considered . .

CHAPTER XXI

Mammals, continued. The markings of counter-shaded mammals: the main types of their
obliterative picture-patterns. Leopards, Giraffes, Zebras, Tigers, Antelopes; Hares,
Ground Squirrels, etc, etc... ee ee

CHAPTER XXII

Mammals, concluded, etc. Patterns of mammals that are not counter-shaded. Sky-matching
patterns of mammals. ‘Sky-pictures’ on the backs and fronts of Skunks, Zorils, Teledus,
Ratels, Ant-eaters, etc. White snow-animals: black markings on white: Ptarmigans,
Weasels, etc. Sky-matching white rumps and tails of many fleet ruminants and rodents
(Deer, Antelopes, Hares, etc.). Flamingoes, Spoonbills, etc., and morning and evening
skies. Other examples of sky-picturing on birds, compared with mammalian sky-picturing.
‘Dazzling-marks,’ fixed and eclipsable; and other special phases of pattern-use. Merriam
cited. Generalizations and comparisons . - cs Aig Bs Ba: ae 82

CHAPTER XXIII

Fishes. Counter-shading universal among them: exceptions: deep-sea fishes: cave-fishes. The
two great divisions of daylight fishes: free-swimmers and the haunters of submerged land.
Flat-fishes: Crabs: Rock-fishes. ‘Paradise’ fishes of the tropics. ‘Mimicry” among
fishes. “Chameleonism” in fishes. Fresh-water fishes. Trout and “trout-spots.”
and Fishes seals. Summary . . oa f SD ca.

CHAPTER XXIV

Reptiles and Amphibians. Counter-shading universal among them. Tree-snakes and -Lizards.
Grass-snakes. Unmarked, striped, and banded snakes. Rattlers, Copperheads, Puff
Adders, etc. Markings of lizards, and chameleonism. ‘“Mimicry” (?) among snakes
and lizards. Crocodilians. Tortoises and Turtles. Frogs and Toads. Elaborate
obliterative coloration—counter-shading and picture-patterns—of certain frogs, toads, and
tree-toads. ‘‘Mimicry” amongthem. Newts,Salamanders,etc.. . .

xill

PAGE

107

119

132

147

160

172

CHAPTER XXV
A PAGE
Caterpillars. Manifold variations of form and habit: manifold variety of devices for conceal-

ment. Predominance of counter-shading: ‘“‘Mimicry”: ‘Obliteration’ and “Mimicry” com-
bined. Inchworms. Luna, Poléphemus, Sphinxes. Leaf-edge caterpillars (on maple,
birch, beech, oak, etc.). ‘Mirror-backed’ caterpillar. Plumed dead-leaf caterpillar.
Dead-leaf-mimicking sphinx. Pine-tuft sphinx. Lappet caterpillar. Concluding re-
Marks. Go .d> ee oe ce Ge we: a gt el SR! Ge Ee Ge ee 8H

CHAPTER XXVI

A glance at Insects other than Lepidoptera (Grasshoppers, Crickets, Beetles, Bees, Wasps, Flies,
Dragon-flies, etc.), and at Spiders. Obliterative shading and picture-patterns on terrestrial
locusts, etc. ‘Dazzling’-colors. ‘Obliteration’ and leaf-mimicry among grasshoppers. Ob-
scure coloration of crickets. Iridescence, ‘ruptive’ patterns, etc., of beetles. Counter-
shading and bark-patterns of cicadas. Plant-lice. Water-insects. Obliterative patterns
of wasps and bees: iridescence. Dim colors and obliterative markings of the Diptera
(Flies, gnats, etc.). Ants. Beautiful obliterative costumes of the dragon-flies: (counter-
shading, vivid colors, iridescence, picture-patterns). ‘Mimetic’ dragon-flies. Larval and
pupal insects . - - - - - «. | . eo. 8 a oe 2 ee t98

CHAPTER XXVII

Butterflies and Moths. Their costumes all concealing, from the gaudiest to the dullest. Changes -
in environments: tropical forests. Earlier estimates of the subject: our limitations. Essay
in English Entomological Society’s “Transactions” cited. ‘‘Mimicry, Common Warning
Colors, and Sexual Selection.” The comparatively small part played by counter-shading.
Immense variety of background-pictures. ‘Sedentary’ and ‘aerial’ butterflies. Kallima
imachis. Other types of leaf-mimicry. Heliconius melpomene: its flight-pattern: its re-
markable roosting-habits. Dainty leaf- and flower-pictures; Metamorpha, Euchloe.
Bark-butterflies: wing-folders; Grapta, Vanessa, Calligo, etc. Ground-butterflies: of the
fields: of the forest. Wing-waving. ‘Intermediates.’ Shadow-color: sunlit-foliage color.
Papilionide. Sun-flecks: sun-streaks: Heliconius charitonia: shimmering foliage. ‘Rup-
tive’ flight-patterns. Hummingbird-Papilios. Heliconius melpomene again. ‘‘Batesian
and Miillerian Mimicry groups.” Clear-winged butterflies: Bates quoted. Iridescence:
major: minor. Morphos: of the tree-tops: of the forest: ‘dazzling’ effect. Obliterative
patterns analysed. ‘Ruptive’ patterns again. Flower-like-ness. The ocellus. Owl (?)
butterflies. Major and minor ocelli. Appendages. Enormous size of butterflies’
wings, relative to their weight: comparison with bees and birds. ‘Obliteration’ of
butterflies’ bodies. Erratic flight. Moths. Urania: ‘target-marks.’ ‘Flat-folding.’
Bright hind wings and masking fore-wings. Marvelously detailed picture-patterns. Near
backgrounds. Flat-folding butterflies. Grass-moths (like ptarmigans and grass-frogs).
‘Obliteration’ and “mimicry.”’ Perpendicularly- and cylindrically-folding moths. Extreme
types of bark-picturing, and peculiar habits accompanying some of them. Dead-leaf
moths. Duality of moths’ and butterflies’ patterns. Nature’s picture-painting again: con-
cluding remarks 2 2) ee eee

xiv

LIST OF ILLUSTRATIONS

COLORED PLATES

PLATE

I—Peacock amid foliage . . - - -
JI.—Male Ruffed Grouse in the forest a, te

III.—Two sketches of male Wood Ducks, in the water Se ct

IV.—Male Wood Ducks. . . .. - -

V.—Colored diagram illustrating the use of ‘ruptive’ coloration

: Frontispiece

VI.—Blue Jays against snow, and Birds-of-Paradise in the tropical forest . . .«
VII.—Cottontail Rabbit among ferns and moss and grasses
VIII.—Roseate Spoonbills, and the skies they picture . F

IX.—Roseate Spoonbill, Red Flamingoes, and twilight sky —-

X.—Flamingoes, at dawn or sunset, and the skies they picture

XI.—Copperhead Snake on dead leaves a.
XII.—Caterpillars (Luna and green sphinx)...

XIII.—Caterpillars (of beech-, birch- and elm-leaf-edges)

XIV.—Caterpillars (of beech- and oak-leaf-edges, etc.). . .
XV.—Caterpillars. (Mirror-back larva, dead-leaf sphinx, frond-bearing Jarva) . .

XVI.—Caterpillar, and spider. (Pine-tuft sphinx, porcelain-white spider) 3. Ses OK

BLACK-AND-WHITE FIGURES

(Photographs from Nature, etc., and diagrams.)

Diagram in the text, 3 figs, Chap.I . . .

FIGURE
1.—Models illustrating the use of counter-shading.

2.—Model illustrating the use of counter-shading.
3.—Models illustrating the use of counter-shading.
4.-—Models illustrating the use of counter-shading.
5.—Models illustrating the use of counter-shading.

Photograph
Photograph
Photograph
Photograph
Photograph

6.—Plymouth Rock hen conspicuous against Plymouth Rock hen skins.

Photograph .

FACING
PAGE
- 38
- 59
« 90
- 497
- 107
- 19
- 147
- 156
- 156
« 172
- 183
- 188
- 192
+ 104
- 196
FACING
PAGE
- %4
- 24
24
24
24
2 24
- 26

FIGURE
7-—White fowl against white cloth. Photograph. - . . . .
8.—White-tailed Ptarmigan in winter plumage, on snow. Photograph -
9.—White-tailed Ptarmigan in winter plumage, off snow. Photograph .

10.—White-tailed Ptarmigan in winter plumage, on snow, but strongly shadowed. Photograph

II.—
12,— pPhotographs of the flat skins of birds and mammals ee Se
13.—

14.—

TS. ,

eee Bird-models illustrating the first principles of pattern-use. Photographs
17.—

18.—Pattern perspective. Diagram ms By o-i:
1g.—Pattern perspective. Diagram. .- . . . 2. «© « .
20.—

or. — (Nesting American Woodcock. Photographs ei Ge cer ok

22.—Nesting American Woodcock. Photograph . . . . . .
23.—Dead Woodcock, with the counter-shading painted out. Photograph
24.—Dead Woodcock on its side, back-view and front-view. Photographs
25.—Nesting Wilson’s Snipe. Photograph . . . . .

26.—Jack Snipe feeding. Photograph . . . . . .

27.—Nesting Whip-poor-will. Photograph -. . . .« .« - .
28,—Nesting Whip-poor-will. Photograph . . . . - «. .

29.—Nesting Nighthawk. Photograph - . . - -. | .
30:—Nesting Nighthawk. Photograph - - - - - = -
31.—Ruffed Grouse walking. Photograph - - +. ~ .
32.—Nesting Ruffed Grouse. Photograph ee we Be
33.—Nesting Ruffed Grouse. Photograph -. . ae) eae

34.—Dead Ruffed Grouse on its side, back-view. Photograph .
35.—Dead Ruffed Grouse on its side, front-view. Photograph. - .
36.—Bit of Great Horned Owl’s wing, and bit of pine forest. Photographs
37.—Stuffed Long-eared Owl in pine-woods. Photograph s
38.—Stuffed Long-eared Owl among evergreen twigs. Photograph
39.—White-tailed Ptarmigan in transitional plumage. Photograph
40.—White-tailed Ptarmigan in summer plumage, nesting. Photograph -
41.—White-tailed Ptarmigan in summer plumage, nesting. Photograph .
42.—White-tailed Ptarmigan in summer plumage, with chick, among rocks.

xvi

Photograph

FACING
PAGE

26
26
26
26

FIGURE
43.—Sage Grouse. Photograph a ae ane
44.—Scotch Grouse (Ptarmigan), nesting. Photograph
45.—Scotch Grouse (Ptarmigan), nesting. Photograph
46.—Young Meadowlarks in the nest. Photograph
47.—Female Eider Duck on her nest. Photograph
48.—Young Short-eared Owls in the nest. Photograph
49.—Yellow Wagtail amid grasses. Photograph .-
50.—Male Bobwhite, nesting. Photograph .
51.—Golden Plover, with chick, in grass. Photograph
52.—Nesting ‘Upland Plover.” Photograph
53.-—Nesting American Bittern. Photograph .

54.—Nesting Virginia Rail. Photograph. . . .

55.—Nesting Wilson’s Tern. Photograph
“56.—
57-—

58.—Chestnut-sided Warbler feeding young. Photograph
59.—Chestnut-sided Warbler (and Catbird). Photograph

60.—Blue Jays amid foliage. Photograph .
61.—Chickadee at nest-hole. Photograph
62.—Oyster-catcher on rocks. Photograph
63.—Guillemots on rocks. Photograph .- . .
64.—Stuffed Goshawk against pine-tops. Photograph

65.—Tip of Goshawk’s wing against pine branches. Photograph
Photograph

66.—Stuffed Goshawk on its back on the forest floor.
67.—Baby Golden Plover. Photograph .
68.—Ringed Plover, at its nest. Photograph. .
69.—Lapwing on its nest. Photograph . .
70.—Killdeer Plover on its nest. Photograph
71.—Killdeer Plover at its nest. Photograph
72.—Baby Killdeer Plover, crouching. Photograph
73.—Nighthawk chick, on the ground. Photograph
74.—Nighthawk chick, on the ground. Photograph
75.—Baby Common Gulls. Photograph

76.—Baby Curlew. Photograph 5
77.—Baby Crested Grebes. Photograph. . .
78.—Baby Red-breasted Mergansers. Photograph

xvii

} Aric monochrome butterflies, against light and dark. Photograph

FACING
FIGURE PAGE

79.—Glinting pool amid grasses. Sketch. . - . -». . « « «© © « «= 82
80.—Baby Horned Grebes on their nest. Photograph. -.- . - . . « - 82
<e } Baby Woodcock. Photographs . .- . -. . . . . - « « « 82
83.—Hairy Woodpecker in winter woods. Photograph (of stuffed bird) and sketch, combined 114
84.—Cottontail Rabbit crouching. Photograph . . eek te 728
85.—Domestic Hare. Photograph - . . &. Be ik & x - 128
86.—Domestic Hare laid on its back. ators F Cae ae : 128
87.—Captive Jaguar. Photograph and sketch (of background) combined - .- - 132
88.—Wild Zebras at a drinking-place. Flashlight photograph #o- & Gt SEBS
89.—Wild Zebras. Flashlight photograph -. . S Gl oc Bs 25 a. E36
g0.—Cardboard zebra, No. 1. Photograph, retouched. . . : <a ey 238
g1.—Cardboard zebra, No. 2. Photograph,retouched . . . . . > ce dh S238
92.—Cardboard zebra, No. 3. Photograph, retouched. . . . a aie ee Ae ES:
93.-—Chipmunk among dead leaves. Photograph. - . . . . . . . - 138
94.—Mbega Monkey. Photograph - - -~ .~ . .«. . . . « « « . 1346
95.—Common Skunk against sky and bushes. . Photograph (stuffed skin) we - 148
96.—Common Skunk against sky and bushes, side-view. Photograph (stuffed skin) - 148
97.—Common Skunk against sky and bushes, nearer view. Photograph (stuffed skin). . 148
98.—Common Skunk against dark. Photograph (stuffed skin) - . « 148
99.—Prairie Skunk against the sky-line. Photograph from stuffed skin ud. Re 148
100.—Prairie Skunk against dark. Photograph from a stuffed skin sw os wo a48
1o1.—Spilogale against sky-line. Photograph from stuffed skin . 2 150
102.—Spilogale against the ground. Photograph from stuffed skin. E 150
103.—A compound picture, of Skunks and Hares. Photographs (and or : 150
104.—Diagram illustrating the use of ‘dazzling’-marks. Photographic ¢ RE. cs - 152
105.—Diagram illustrating the use of ‘dazzling’-marks. Photographic 3 - 152
106.—Diagram illustrating the use of ‘dazzling’-marks. Photographic . -. -. . . 82
107.—Stuffed Prong-buck, rear-view, against sky. Photograph a ee ee 154
108.-—Stuffed Prong-buck, rear-view, against ground. Photograph . . 5 154
109.—Stuffed Prong-buck, half side-view, silhouetting against sky. Photograph - 154
110.—Prong-buck as in Fig. 109, but photograph shaded to suggest night-effect. PhetieraDs
retouched Be Se oe os P 3 - 154
111.—Deer or Antelope aithanateea against ign sky. Sketch e 4 . - 154
112.—Dead Hare, rear-view, against sky. Photograph = OF An UB el OS oa ae gy
113.—Dead Hare against ground. Photograph er ge ve EE ce cep CS) NTEY

xvill

FIGURE
114.—White card againstsky. Photograph . . . . .
115.—-White card against ground. Photograph 29 oe cha

116.—-Imitation Egret, without plumes. Photograph
117.—Imitation Egret, with plumes, against dark. Photograph
118.—Imitation Egret with plumes, against white. Photograph
119.—Diagram illustrating the effect of certain patterns. Drawing

120.—Fifty little pictures, mainly photographic, of real holes, and of counterfeit holes in animals

patterns) om Ge) em wm ae
121.—Green Snake, right-side-up. Photograph -
122.—Green Snake, inverted. Photograph ese
123.—Rattlesnake among stones. Photograph and drawing .
124.—Brown Lizard on apple-tree bark. Photograph . . .

oa } Brown Wood Frog among dead leaves. Photographs
126.—

127.—Common Garden Spider on its web. Photograph Se
128.—Orange-tip Butterflies on cow-parsley. Photograph . .

129.—Butterflies on vegetation. Photograph . .

130.—Light butterfly with shadow-colored fore-wing borders. Photograph .

131.—Small Tortoise-shell Butterfly on pebbles. Photograph 7
132.—Ocellus on a butterfly-model. Photograph . os ¢

133.—Moths, Butterfly, and Pheasant’s tail, on dead leaves, etc. Photograph .

134.—Two Grass-moths, on grass. Photograph .

135.—Tiger-moth on sprig of Box. Photograph ee
136.—Four Bark-moths, on Maple bark. Photograph . . .
137.—T wo Bark-moths on Pitch Pine. Photograph . . .
138.—Three Bark-moths, on Gray Birch. Photograph. . .
139.—Pandorus Sphinx Moth on a White Birch tree. Photograph

140.—Bits of sphinx-moth pattern and of bark-pattern intermingled.

xix

Photographic

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CONCEALING-COLORATION

IN THE

ANIMAL KINGDOM

INTRODUCTION

HILE man has gone on wresting from Nature one deep-buried secret

after another, the whole field of protective coloration has lain un-

concealed, inviting recognition, resplendent with wonderful and beautiful

phenomena. Yet of these he has remained uncognizant, or caught only

fragmentary glimpses, piecing together the fragments with the aid of false

hypotheses, which have presented such a spectacle of inconsistency as to
bring the whole subject into widespread contempt.

The entire matter has been in the hands of the wrong custodians. Apper-
taining solely to animals, it has naturally been considered part of the zodlo-
gists’ province. But it properly belongs to the realm of pictorial art, and can
be interpreted only by painters. For it deals wholly in optical illusion, and
this is the very gist of a painter’s life. He is born with a sense of it; and,
from his cradle to his grave, his eyes, wherever they turn, are unceasingly at
work on it,—and his pictures live by it. What wonder, then, if it was for him
alone to discover that the very art he practices is at full—beyond the most
delicate precision of human powers—on almost all animals? Fortunately,
although this search, like all others, requires a specialist, the beautiful things
discovered are appreciable by all men; and our book presents, not theories,
but revelations, as palpable and indisputable as radium or X-rays.

Naturalists have not understood the principles of objects’ distinguishability.
Let us first consider the part distinguishability plays in animals’ lives. Sight,
in the great majority of cases, is the sense by which at the last moment the
quarry’s fate is decided. Had the cougar, wolf, or fox no eyes, he would
starve. Had the hare no sight, he could not tell when to abandon his
squatting and spring away, or which way to dodge the murderous leap that
would follow. Scent brings the predator along the trail or up-wind nearly to
the game, but were this pursuer blind, he would seldom (except in

holes) * catch anything more active than a tortoise, as everyone knows who
has watched a cat, dog, or ferret falteringly nosing out the whereabouts of a
bit of flesh, or a setter pointing a bird. The dog commonly points the stream
of scent that is passing his nose, without the slightest appearance of knowing
where the bird is. In fact, for the purpose of knowing just where their game
is, scent offers animals no immediate aid; and the same is true of sound. For
scent and sound can go round corners, whereas sight operates solely in a
straight line. Sight is also out of all proportion the swiftest; for while scent
moves practically only at the air’s rate, and sound only 1,121 feet a second,
light, which means sight, travels 182,000 miles a second! This combined
straightness and swiftness gives sight, and sight alone, the power to tell the
predator exactly where his quarry now is, and the quarry where his enemy is.
Thus, at these crucial moments in the lives of animals, when they are on the
verge of catching or being caught, sight is commonly the indispensable sense.
It is jor these moments that their coloration is. best adapted, and, when looked at
jrom the point of view of enemy or prey, as the case may be, proves to be ‘ obliter-
ative.’ All experiment corroborates our supposition that human and animal eyes
bear essentially similar relations to light vibrations. (And, in fact, almost all
theories about the functions of animal’s colors are based on this hypothesis.)

All naturalists perceive the wonderful perfection of the twig mimicry by
an inchworm, or of bark by a moth, or of a dead leaf by the Kallima butter-
fly. It is now apparent that almost equally marvelous concealment-devices,
in one shape or another, are general throughout the animal kingdom; the
most gorgeous costumes being, in their own way, climaxes of obliterative color-
ation scarcely surpassed even by moths or inchworms.

This discovery that patterns and utmost contrasts of color (not to speak
of appendages) on animals make wholly for their ‘obliteration,’ is a fatal
blow to the various theories that these patterns exist mainly as nuptial dress,
warning colors, mimicry devices (i. e., mimicry of one species by another),
etc., since these are all attempts to explain an entirely false conception that

* In the case of the weasel family, this exception is doubtless a large one.

such patterns make their wearer conspicuous. So immeasurably great, in the
case of most animals, must be the value of inconspicuousness, that such de-
vices as achieve this to the utmost imaginable degree, upon almost every liv-
ing creature, demand no further reason for being (although doubtless serving
countless other minor purposes).

The theory of Natural Selection is based on the belief that organisms are
susceptible of modification limited only by the duration of the circumstances
causing it, or by the attainment of ultimate perfect fitness to environment.
Now, since the same circumstances would always be best met by the same
characters in an organism, we are not surprised to find all animals, of how-
ever widely different orders, resembling each other in shape and color in evi-
dent proportion to their degree of having the same habitat and habits. The
whole class of mammals, dwelling mainly on the ground, have mainly ground
color, and a form varying no more than their situations and habits. The
same thing is equally true of thousands of species of birds, of fishes, reptiles
and insects; even mammals, if they lead a fish’s life, like the cetaceans, have
the general shape and color of fishes. (A parallel case is that of humming-
birds and hawk moths.) No fish of the open ocean is permitted by Nature
to wear any essential color-distinction from his hundreds of neighbor species.
He has, for all we know, the same need of ‘‘ warning colors,” “‘banner marks,”’
etc., as any land animal; but Nature vouchsafes him no pin-point of color be-
yond that of the sky-lit deep-sea water. ‘The same is true of the inhabitants
of the aérial ocean spaces. Save for a good many small, bright-colored dec-
orations, mainly of the beaks, worn by such species as breed where such col-
ors abound, Nature allows them no colors which are not those of sea surfaces,
clouds and sky, or of somber cliffs; or, for the diving ones, dim water-colors,
more like those of the fishes themselves. In short, the so-called “nuptial
colors,” etc., are confined to situations where the same colors are to be found
in the wearer’s background, either at certain periods of his life, or all the time.
Apparently, not one “mimicry” mark, nor one “warning color” or “banner
mark,” nor one of Gadow’s light-and-shadow-begotten marks, nor any “‘sex-

ually selected” color, exists anywhere in the world where there is not every
reason to believe it the very best conceivable device for the concealment of its
wearer, either throughout the main part of this wearer’s life, or under certain
peculiarly important circumstances.*

These deceptive patterns, painted by Nature on the exteriors of almost all
animals, will prove to be an inexhaustible field for studying their psychology.
Stevenson makes Alan Breck say ‘“‘Them that cannae tell the truth, should
be aye mindful to leave an honest, handy lee behind them. If folk dinnae
ken what ye’re doing, Davie, they’re terrible taken up with it; but if they think
they ken, they care nae mair for it than what I do for pease porridge.” The
psychological principle in this lies deep in Nature’s artifices for concealing
animals. Wherever, for instance, the animals are habitually to feed amidst
brilliant vegetation, she is apt to give brilliant marks rather than simply equip-
ping them to match the soberer interstices amidst the brilliant details. The
principle is, evidently, that amidst a large number of similar striking objects,
an imitation of these has the support of the credit of all the real ones. ‘There are
before the eye so many obviously real ones, that the mind refuses to take the
trouble to suspect any. For a red mark on a bird, fish, or butterfly to pass
itself off for a red flower among many red flowers is like Alan’s telling the
passer-by that his errand is such a familiar one as the search for a runaway
horse; while, in such a situation, to try to escape notice by imitating a dusky
place, may be as much more risky as for Alan to assert merely that he is not
on a mysterious errand.t The so-called “‘nuptial’’ costumes of animals are

* Plainly, most details of an animal’s body serve many purposes; and whatever law develops
the detail’s main characteristics,.doubtless causes it also to be modified to meet each minor use, in the
degree of its relative importance. To illustrate with human experiences, the hunter’s rifle, besides
its main use, serves also at times the purpose of a balancing-pole, or even a club; and, carried over
his shoulder as he goes away, it serves to show his family that there may be venison for dinner; yet
its essential purpose is to Rill that venison,—for this, nothing but a rifle would serve. In the same way
animals’ markings doubtless serve in various lesser degrees most of the purposes that have been
attributed to them.

+ Another good analogy is the universal human propensity to trust circumstantial evidence too
much; to believe any accused person guilty, because the sin he is accused of is a common one.

demonstrably an increase of such potency of obliterative coloration as belongs
to all gorgeously varied costumes, and this at the very period when concealment
is most needed.

It is of great importance to understand that skill and strength are not all
confined to predators. It is plain, upon any hypothesis whatever which rec-
ognizes the existing fitness of all forms of life to their uses, that this fitness is
presumably just as great in the quarry’s case as in the hunter’s. The fleet-
ness and alertness of the hare are a good match for the stealth and power
of the lynx, etc., and the consequent balance between predator and prey is
doubtless known to the instincts of each animal. The lynx’s obliterative col-
oration just as much increases his dangerousness to the hare, as that of the
hare adds to the lynx’s difficulty in catching him.

Although inconspicuousness is merely an approach to indistinguishability
(of course this positive term refers only to occasional effects), yet the practical
workings of the two are worth considering separately. Indistinguishability
enables predators to ambush their prey, and, on the other hand, it protects
any quarry to the windward of which the predator may pass (if he is not trail-
ing it). Mere inconspicuousness of the predator causes him to be less avoided
by the animal he preys on, while for the prey it means a minimizing of the
stimulus he gives to his enemy’s rapacity. Also, at the ultimate moment
both sides profit by showing as indistinctly as possible, so that the rapacious
animal is harder to dodge, and the prey a fainter target to strike at. Sports-
men, insect-catchers, and tennis players will understand this. Again, in a
very large class of cases the question is not whether the hawk, for instance,
can espy, or the fox, scent, his game, but whether there appear to him, at the
moment, sufficient advantages on his side to stimulate him to an effort such
as has far more often failed than succeeded. Also, a single instant of success-
jul disguise suffices to protect an animal from a swiftly passing marauder, a
hawk, for instance. In a rapacious animal’s case there must be an eternally
shifting balance between greed and imertia. Doubtless a sufficiently strong
incentive—a very obvious chance—might rouse even the most gorged of

hawks to attempt another capture; while, on the other hand, one that was
starving, or whose young were, would achieve marvels of daring and power.
Watch an Accipiter sitting amidst the usual abounding bird life of summer
woods. You will often look long for any sign that the small birds fear him,
or that he threatens them. One evidence that this balance of circumstances
is what keeps the two classes of animals so peaceful in their general demeanor
toward each other is to be found in the alacrity with which predatory animals
rush to investigate an imitation of a bird’s or mouse’s cries of distress. So,
too, a pickerel, after long listlessly watching your bait, with the barest signs
of interest, will often seize it the moment it gets foul of a lily pad and seems
in difficulty. Other things being equal, animals that hunt by sight (i. e., do
the whole thing by sight, as hawks do in distinction from most rapacious
quadrupeds) would try for the most conspicuous prey, just as a sportsman is
almost irresistibly drawn to shoot at the best mark in a flock of birds—so
much so, that, if he be a beginner, he may let them all go by, after swinging
his gun upon one after another of them, unable to keep to the one first se-
lected, when another has become more conspicuous.

Just as men who live amidst constant danger have powers of instantane-
ous action unknown to farmers and shopkeepers, so the hare and the deer
have acquired in their hard school similar alertness and speed. In terms of
the theory of natural selection, the quarry has had just as many centuries to
learn his part, as the predator to learn his. Evidently, the hawk’s nerves know
this so well that, instead of wasting energy, they, so to speak, ‘take into their
own hands’ the business of being ever ready to hurl him like lightning on a
disabled or preoccupied victim.

Since we may assume that there zs this closest balance between the respect-
ive powers of predaceous animals and their game, it follows that, in the long
run, smallest advantages will tell. And if they do tell, the same process, what-
ever it be, that has adjusted moths to bark and made inchworms look exactly
like twigs, must be everywhere at work, carrying each advantageous trait to
similar perfection.

In the days of swordsmanship, there was little difference between fine
fencers, yet the best one would, by the most delicate shades of superiority, get
his sword through his opponent’s ribs in one fight after another till all men
feared him. That such things are more than luck is well known to life-
insurance companies and army recruiters. Why do they take no chances,
but, instead, calculate averages, and reject each applicant whose defects exceed
the limit, even in cases where this applicant has a great many chances of con-
tinued health—where he may outlast sounder men? If war departments
know that minute defects in individual soldiers will affect even a single cam-
paign, how is it conceivable that, in the animal kingdom (if there be natural
selection at all, or any corresponding principle), hundreds of thousands of
years should leave any sifting unperfected, any slightest adaptation incom-
plete? All characters, barely noticeable by us, but which are in the long run
of more use than harm, must develop.

This book demonstrates that the colors, patterns, and appendages oj ani-
mals are the most perfect imaginable effacers wnder the very circumstances wherein
such effacement would most serve the wearer. For any particular animal to
be seen looking conspicuous means no more than that he is not at those
moments looked at under the circumstances for which his concealing-colors
are effective; and man’s persistent misconception that bold patterns, etc.,
make the wearer conspicuous, is based on a psychological principle. Let us
imagine one hundred butterflies of the same species within range of a nat-
uralist’s sight, and ninety-nine of them concealed from him by the effect of
their bold patterns, while the hundredth happens to be noticed by him, and,
of course, identified by all its attributes, bold pattern and all. What impres-
sion about the species has this naturalist gained through this experience? He
carries away simply one more mental picture of a butterfly of this boldly
patterned species, and mistakes its specific recognizability for intrinsic con-
spicuousness. ‘The ninety-nine successful disguises have made no impression
at all. So he goes on, accumulating a conviction that the species is conspic-
uous. He can tell you a long list of cases to prove it:—while the actual case

is, that for every one he saw there were as a rule scores, within range of his
sight, concealed by the very patterns which he believes to make the species
conspicuous! I had, lately, a chance to prove all these things upon a natural-
ist who believed, as has always been held, that ‘‘conspicuous”’ patterns, etc.,
make conspicuous objects. Of each species that he declared to be a con-
spicuous one I arranged either a stuffed specimen or a good imitation, and
placed it full in his sight, out of doors, in the most natural of situations. And
each time he was amazed at failing to find it conspicuous. In every case of a
series of such tests, he discovered the specimen only after a more or less long
search.

One case is enough to cite here. He declared a coral snake, with its red,
black, and gold rings, to be ‘‘the most conspicuous object in Nature.” I
placed on bare ground some imitation snakes—one black, one scarlet, one
gold, one earth-color, and one good facsimile of a coral snake, with its bright
scarlet, gold, and black rings, and the counter shading universal among snakes,
and invited him to look at them from a distance of about twelve yards. He
saw at once all but the coral snake, and would never have known the latter
was there had he not been told. Yet in this case he had been told just where
to look, on a bare open space of flat ground.

I asked him if he still believed that a naturalist’s eye takes in most of the
coral snakes that come within its range in the complex scenery of the jungle!
By such experiments all his beliefs on the subject were one by one confuted,—
as, in the end, he most openly and generously acknowledged.

Concealing-coloration means coloration that matches the background. But
since an object’s background varies with the point of view, there can be
no such thing as complete, intrinsic inconspicuousness. ‘The means of ob-
jects’ recognizability, no matter how they are colored or marked, is almost
always their silhouette—i. e., their outlines in ‘relieving’ darker or lighter
or differently colored against their background. If an object moves about—
or, what amounts to the same thing, if the beholder moves about—the object
is bound to silhouette in various ways against various backgrounds. If the

object moves about ouddoors, in sunlight and in shadow, this versatility of
silhouetting becomes extreme. Day’s vast chiaroscuro can make the black-
est objects ‘relieve’ bright against dark shadows, and the whitest objects
‘relieve’ shadowy dark against the light. Given a sufficient freedom of
motion on the part of object or beholder, and, aside from changes in the
object’s own illumination, its backgrounds are bound to range through this
whole scale of variations and contrasts, from earth and its darkest shadows
to sky and its brightest lights. Patterns on animals’ coats are the utmost that
Nature can do in opposition to these potent vicissitudes of silhouetting. ‘This
is the point at which Darwin, Wallace, and others went wrong; and this in
spite of the fact that their supposed ‘‘conspicuous” species are, doubtless,
more easily detected, in the long run, than their “cryptic” species. It is
true that if one sits still in a wild place one will usually detect more individuals
of the so-called conspicuous kinds. But this is because they are mostly ar-
boreal or aérial species which a terrestrial observer is apt to see against a much
wider gamut of background than that to which the so-called cryptics are sub-
jected. ‘They are the ones that have to move about most freely in sunlight
and in shade, and against all manner of backgrounds, from shining sky to
the darkest forest shadows. Their bold coloring, however, minimizes, not
increases, their conspicuousness in this difficult situation, where the more
nearly monochrome so-called cryptics, adapted for ‘‘sticking close” to tree
trunks or the brown ground, would be comparatively conspicuous. One
animal most needs to escape observation from above, another from below,
and others equally from all directions. It follows that some must be colored
to match brown ground, some to match the sky, or sky and foliage, while
some must have costumes combining these extremes; and just such wonder-
ful adaptations, in highest development, prove to be universal. Animals,
therefore, are conspicuous when seen from any but the right view point—white
sky-matchers showing bright against the ground, brown earth-matchers sil-
houetting dark against the sky, etc.,—with all the magic of their concealing-
costumes lost. Again, it follows that we should be inclined to count con-
II

spicuous those species which we most commonly see against the wrong back-
ground. This is what Darwin and Wallace did,—and, failing to understand
the effect both of pattern and of visibility through contrast and silhouette,
they made the fundamental mistake of ascribing the conspicuousness to the
very thing which opposes it. Their immense prestige has so riveted this
error in students’ minds as to have doomed the whole subject, hitherto, to
confusion and neglect.

Naturalists repeatedly experience the difficulty of detecting brilliantly
colored birds and strongly marked quadrupeds—commonly recording each
case as surprising or inexplicable under the supposed circumstances, or some-
times manifesting a true apprehension of some one particular case, without
seeing that they are dealing with a universal principle.*

Among the aboriginal human races, the various war-paints, tattooings,
head-decorations, and appendages, such as the long, erect mane of eagle
feathers worn by North American Indians,—all these, whatever purposes their
wearers believe they serve, do tend to ‘obliterate’ them, precisely as similar
devices ‘obliterate’ animals.

The color-relations of earth, sky, water, and vegetation are practically
the same the world over, and one may read on an animal’s coat the main
facts of his habits and habitat, without ever seeing him in his home.

ApBBott H. THAYER.
Monapnock, N. H., December 15, 1907.

* Here is a simple way to discover whether one has the full color sense necessary as a basis for
studying obliterative coloration. If, like a multitude of people, one cannot see that shadows on an
open field of snow, or on a white sheet, under a blue sky, are bright blue like the sky overhead, one
will probably prove more or less defective in all color-perceptions. To prove that such shadows
are sky colored, lay a colorless mirror on the snow in such a shadow,—its reflected sky will match the

surrounding snow.

CHAPTER I

GENERAL OUTLINE OF THE BOOK’S SCOPE. THE ‘‘LAW WHICH UNDERLIES
PROTECTIVE COLORATION”? INTRODUCED

“ FYROTECTIVE COLORATION,” with its achievement of the wonder-
ful inconspicuousness of many wild animals in their native haunts,
has been recognized since the earliest days of Natural History study. But the
true character of this phenomenon has been ignored or misinterpreted, and
the phenomenon itself has been observed only in one small corner of its wide
field of action. It has waited for an artist, in the last years of the nineteenth
century, not only to recognize the basic working lcws of protective colora-
tion, but to perceive that the many animals of supposed “cor picuous”
attire are almost all colored and marked in the way most potent to conceal
them.

We will begin with an exposition of the long-ignored laws involved in such
protective coloration as has been generally noticed, leaving to be developed
in later chapters the revelation of its larger scope.

Since time immemorial, human hunters must often have been aware of the
strange elusiveness of motionless deer in a brown landscape, or of hares or
partridges squatting on the ground. ‘Those who stopped to seek the cause of
this, perceived that the deer or partridge looked almost exactly like the land-
scape or the ground in color, and were satisfied with this explanation; and
thus was evolved that stock phrase of nature students, which has found a
place in almost all books about animals, that these inconspicuous creatures
are “colored like their surroundings.’”’ But it is our first task to. show that
this logical-seeming and universally accepted explanation is inadequate and
misleading, and to vindicate the paradoxical-sounding statement that if crea-

tures were purely and simply “colored like their surroundings” they would not
be inconspicuous at all. This has already been explained by articles in several
scientific and popular magazines, but the explanation must be repeated here
in full for the benefit of those who have not seen the former expositions of the
discovery. What people commonly fail to perceive in connection with this
matter, is that the exposition is really that of a discovery, i. e., of an indis-
putable optical fact, hitherto unnoticed, and not merely that of one more
theory. It is the revelation of how animals’ wonderful inconspicuousness in
their normal haunts, recognized for centuries but in its essence never under-
stood, is really achieved. That is, not a description of any course of evolution
or process of pigmentation, but the revelation of the manner in which the
existent system of coloration renders animals nearly invisible on their native
heath.

I will quote, with slight modifications, from the original article published
in 1896, and from that published in Nature in 1902.

“The newly-discovered law in its application to animals may be stated
thus: Animals are painted by Nature darkest on those parts which tend to be
most lighted by the sky’s light, and vice versa. The accompanying diagram
illustrates this statement.

‘‘Animals are colored by Nature as in A, the sky lights them as in B, and
the two effects cancel each other, as in C. The result is that their grada-
tion of light-and-shade, by which opaque solid objects manifest themselves to
the eye, is effaced at every point, the cancellation being as complete at one

point as another, as in C of the diagram, and the spectator seems to see right
through the space really occupied by an opaque animal.” In the Nature
article this was reworded and emphasized as follows: “If an object be colored
so that its tones constitute a gradation of shading and of coloring counter to
the gradation of shading and of coloring which light thrown upon it would
produce, and having the same rate of gradation; such object will appear
perfectly flat;—retaining its length and breadth, but losing all appearance of
thickness; and when seen against a background of color and pattern like its
own will be essentially indistinguishable at a short distance. All persons
who have seen the models which illustrate this, know that they prove it.
Now, if this stands proved, the fact that a vast majority of creatures of the
whole animal kingdom wear this gradation, developed to an exquisitely mi-
nute degree, and are famous for being hard to see in their homes, speaks for
itself. It is plain that their color-gradation can no more escape effacing
their look of solidity than the law of gravitaticn can escape drawing a pro-
jectile to the earth. This is so obvious, that one hears on all sides expressions
of wonder that it was so long unnoticed. I may add that all persons of trained
sight, such as artists, perceive it everywhere among wild creatures. Other
people supplement their undeveloped sight-sense by their other senses, and
if they know an animal 7s solid, think he Jooks solid.

“Let anyone look at a ball, or egg-shaped object, anywhere out of doors,
and when he has recognized its shading, from its light side to its dark, try to
so color it, where it stands, as to efface this shading. If he succeed, he will
find that Nature has swiftly guided him through the same process which has
taken her so long on the coats of animals, and that he has given the object the
counter-gradation I speak of; and it will have dawned on him that so long as
light makes its one gradation on objects, there is only the one way to neutralize
it. In short, I simply prove that this arrangement of animals’ colors is what
so marvellously effaces them, and leave it to others to discuss the question
whether concealment be a benefit to an animal, and whether the fact that it is
a benefit be the cause of his being concealed. All who believe in Natural

Selection, however, will of course feel that this color-law is its work; and
since it is so almost universally in use, and accounts, apparently, so almost
exhaustively, for all the attributes of graded animal coloring, I believe it will
ultimately be recognized as the most wonderful form of Darwin’s great law.”

The foregoing extracts together fully state the newly-revealed principle,
which in its various elaborations is the foremost subject of the present book.
But it may be well before going further to dwell at greater length on the sim-
plest aspect of this fundamental principle.

No one who has studied animals in nature can have failed to notice either
their frequent wonderful inconspicuousness, or the fact that ninety-nine per
cent of them are dark colored on the back and light colored on the underside.
On the other hand, even school children are daily taught that the only way
to draw a representation of a ball or cylinder is to shade it from a bright
central point or middle line to dark borders—or, if the object is to be shown
in side view, under a top light, to shade it from very bright above to deeply
dark below. Yet the obvious conclusion that the contrary gradation of
shades, as it exists on the rotund bodies of animals, is the cause of their wonder-
fully unsubstantial appearance, has never been drawn till now, and even now
is but slowly accepted by most people. This is because few people recognize
the vast part played in the visible world by light-and-shade. As has already
been said, the known fact of solidity suffices, to many minds, without any
inquiry into the means by which that solidity is manifest to their sight. Light-
and-shade, color, and line, are the three great factors of visibility. Line
perspective enables the eye to judge to a large degree of the forms of objects,
and the various distances of their different parts, especially in the case of large
ones of elaborate shape, such as buildings; but the visibility of line is de-
pendent on color, and still more on light-and-shade. I here use ‘line’ to
mean the visibility of the boundaries of material surfaces and their parts.
It is obvious that this is dependent on color, since if a monochrome flat sur-
face is so placed relative to the eye of an observer that one of its boundaries
is against another flat surface of precisely the same color, and similarly lighted,

that boundary will be invisible; and it is just as evident that it is dependent
on light-and-shade, since two objects of like color can be differentiated, and
two of different colors can be made to appear to blend together, by effects
of shadow and light. Light-and-shade is more important than color, because
it is primarily an attribute of form, while color is only secondarily so. The
reader should look at his hand, or any other small object of elaborate form,
and consider the factors of its appearance which enable his eye to perceive
it, in its entirety and its details. The form and position of the various por-
tions are revealed by the lines of perspective, and by the light-and-shade,
that is, the shadows on those parts which are most averted from the prevailing
light, and the points of high-light on the reverse portions. We have already
seen that these main factors are interdependent on each other. Color, the
third factor, plays a much smaller part. A projecting portion, for instance,
may be of a different color from the rest, and will then be distinguishable
from it by its color alone, but without the line and light-and-shade it would
appear merely as a spot of color on the general surface—the projection would
not show as such, except in so far as its peculiar color revealed its character-
istic outline,—when, as in the case of the counter-shaded animal, the fact of
its solid form would be mentally inferred, rather than actually seen, by the
observer. On the other hand, there is the color difference between the sur-
faces which more directly catch the bluish sky-light, and the relatively orange-
colored shadow-portions, etc., aside from other possible color incidents of
reflected light; but these are secondary factors, since if the whole object were
of a uniform neutral tint, and the color effects of the light were eliminated,
the visibility of its various parts would scarcely be decreased. (Drawings in
black and white, and photographs, are excellent exponents of this principle.)
In just this way the form-variations of all solid objects are revealed to the eye
—according to the simple law, that depressions lose light and are therefore
darker, and elevations gain light and are therefore brighter; surfaces averted
from the prevailing light being equivalent to depressions, and those turned
toward it to elevations. It is, then, primarily by the light-and-shade on solid

objects, that the eye is made aware of their existence, their main form, their
position, and all their minor modelings. Now, since this is the case, it follows
that animals, however colored, would always be more or less conspicuous in
their natural environment, and all the details of their form would be dis-
tinctly visible, unless their surfaces bore such an arrangement of light and
dark shading of the colors as could counteract the shading which the de-
scending daylight applies to their solid bodies. This counter gradation of
shades, from dark mid-backs to white mid-bellies, is, as we have seen, pre-
cisely the system of coloration (‘Mimicry’—vide Chapter II—aside) of
almost all protectively colored animals.

The ghostly elusiveness of a counter-shaded creature’s appearance is at
its best under a diffused sky-light, such as that in the forest, or the open fields
on a cloudy day, because no color gradation can adequately cope with the
full and concentrated light of the sun itself, which produces sharply contrasted
areas of light and shadow, rather than a graduated shading. Even in full
sunlight, however, the light from the wide expanse of sky is still the principal
factor. To understand this, the reader should compare the difference between
a sunlit patch of ground and a neighboring one which is cut off from the direct
sunlight, with the difference between the latter and the mouth of a deep hole
which is cut off from both sun- and sky-light. The one is the slight difference
between a sunny and a shady spot, the other is the vast difference between
night and day. A patch of bright sky no bigger than the sun is far less brilliant,
but the vast sum of such patches which the entire expanse of sky contains,
yield a far greater light than the sun itself. (This is analogous to the principle
of sound, which makes the sum of the concurrent echoes of a clap of thunder
far louder than the initial sharp electrical report itself.) An animal’s
counter shading, then, is effective even on open ground on a sunny day,
although the superadded direct sunlight interferes with the perfection of
its working.

On this basis of the obliteration of the light-and-shade aspects of a solid
creature, the most exquisite color resemblances to the creature’s background

are achieved; on no other basis could they be achieved, or would they greatly
avail the animal. (See, however, the definition of Mimicry in Chapter II.)

The reader who has assimilated what we have said thus far, is now in a
position to perceive the fallacy of the statement, prevalent in former years,
and still made by certain writers, that a protectively colored animal of the
type described above escapes detection because, being of a dull-brown color
like the ground and the bushes, it looks when it sits motionless like a clod or a
stump—or some such inanimate thing. For clods and stumps are solid
objects of a uniform tint, and manifest to the eye, by the laws of light-and-
shade, not only their solidity, but all their smaller modelings. They are not
inconspicuous, except in so far as their great abundance makes the eye in-
attentive to individual ones. The protectively colored animal, on the other
hand, is, as it were, obliterated by his counter-gradation of shades, and in
the cases where he escapes notice, it is by virtue, not of the eye’s perceiving
his solid form, and taking it for that of an inanimate object, but of its failure
to recognize it as a solid object of any kind, seeming, if it rests on it at all,
to see through it to what is beyond. For the animal looks at most like a flat
plane interposed between its background and the observer; and since actual
flat foreground-planes of this kind at right angles to the earth do not com-
monly exist in the woods and fields, the eye usually interprets the animal’s
surface as part of the scene, ground-plane or wood mass, simple or com-
pound, which lies beyond it. If these animals were merely brown or gray
like clods and stumps, they would not be concealed, because their structural
forms are too distinct, and the eyes of enemies are keen to detect their charac-
teristic ‘modeling’ and outlines. On the other hand, a perfect shade-
gradation, even of some rankly brilliant color, would go far toward concealing
an animal, for he would still have no appearance of solidity; and any varied
landscape, especially a sunlit one, even in the dingy temperate zone, is full
of patches of brilliant color, as all artists know.*

* A large expanse of any strong color, as the green of the foliage, begets in its interstices and on
its borders an appearance of its ‘‘complementary.” It is partly for this reason, as an American

A striking revelation of how completely the inconspicuousness of counter-
shaded creatures depends upon their counter shading, may be had even more
easily than by experimenting with models, merely by holding such a creature
upside down, in its normal lighting, and against its normal background. It
will be seen not merely that its ghostly dimness has vanished, but that it is
extraordinarily conspicuous—just doubly as conspicuous, in fact, as any stick
or clod placed in the same position would be. For an inverted animal not
only lacks counter shading, as a stick or clod does, but is even fully shaded
the wrong way—brightest where it catches most light, and darkest where it
catches least. No other conceivable arrangement of colors could make an
object as conspicuous as this. Yet an animal held thus inverted is, materially,
as truly “colored like his surroundings” as he ever was. It might be thought
that such creatures are usually seen from above, so that their light-colored
undersides are out of sight, and that only their wpper parts, which always
show, are supposed to be colored like their surroundings. ‘To this there are
two cogent answers: In the first place, many of these creatures, such as the
various forest Grouse, are at their best when perched high above the ground,
so that the under side is at least as fully exposed as the upper. In the second
place, the colors of those which stay on the ground must surely serve as a
protection against the ground animals, which move about on their own level,
as much as against those which see them from above, as do hawks and men.
This last is a very important consideration, with which we shall have to deal
again later in the book.

In speaking of the elements of visibility, I have already referred to the fact
that color—apart from light-and-shade—is a secondary factor in the visibility
of the ‘modeling’ of solid objects, and have spoken of the tendency toward
a bluish coloring of the more directly sky-lighted portions, and an orange
coloring of the reverse ones. The working of this principle on the bodies of
animals is very pronounced, and the counter gradation of their tones would
ornithologist, Mrs. F. H. Eckstorm, has very truly said, that the gorgeous Scarlet Tanager is not
conspicuous in the green woods.

not be perfect if it did not include a delicate gradation of actual color, from
brownest above to bluest below, to cancel the effect of the bluish sky-light
and shine on their upper surfaces, and the brownish shadow, with brown earth-
reflections, on their lower. Cold white is usually required for the bright
climax of the shade gradation, and cold white amply meets the color require-
ment also. It is likely that few but artists will feel the validness of our state-
ment of this subtler element of the principle, although anyone can learn to
see the existent gradation of ‘color’ on most counter-shaded animals.

The reader has now been given a fairly exhaustive description of the main
elements of the new principle, which through its various windings and with its
various remarkable concomitants we are about to follow into several branches

-of the animal kingdom. Among the lower orders, it is more or less largely
supplanted by another great principle, namely, that of Mimicry, which we
will define and differentiate in Chapter II.

Before closing this introductory chapter, however, we must give an account
of the earlier, independent partial discovery of the principle of counter shading
in the animal kingdom, by Prof. Edward B. Poulton, of Oxford University.
Professor Poulton has been one of my father’s most enthusiastic listeners,
and is one of the few naturalists who have given proof of completely under-
standing the subject. In his introduction to my father’s article in Nature
he generously seeks to minimize the importance of his own partial predis-
covery of the principle.

The case is thus stated by my father in the above-mentioned article:

“Since publishing my papers in ‘The Auk’ for April and October, 1896,
I find that Prof. Poulton perceived years before their appearance the power
of a counter-grading of light to make the round surface of a pupa appear
flat, and in another case the power of light color in a depression to make the
concavity disappear. In both of these cases he perceived the very Law of
Light-and-Shade on which the fact of Protective Coloration rests, and recognized
the fact itself in these instances. In his ‘Notes in 1886 upon Lepidopterous
Larve, etc.,’ read April 6, 1887, he says (Trans. Ent. Soc. Lond., 1887, p.

294), ‘Although the cleft (between the posterior part of the body of the larva
of Rumia crategata and the branch) is largely filled up, . . . a considerable
furrow remains, but this is not apparent because of the light color of the
fleshy processes, which prevent the attention from being directed to the shadow
which would otherwise indicate the position of the groove. The processes,
therefore, attain the object of softening the contact between the larva and
its food-plant in a two-fold manner, by partially filling up the cleft and by
neutralizing the shadow in the groove which remains. I have also noted the
processes in the larva of A. betularia, and I believe that they are of very general
occurrence in Geometre.’

“His other case is to be found in his ‘Notes in 1887 upon Lepidopterous
Larve, etc.,’ read October 3, 1888. He says (Trans. Ent. Soc. Lond., pp.
595-6), ‘The most extraordinary thing about this resemblance (of the pupa
of A patura iris to a sallow-leaf) was the leaf-like impression of flatness con-
veyed by a pupa which was in reality very far from flat. Thus the length
of the pupa was 30.5 mm.; the greatest breadth (dorso-ventral diameter)
11.5 mm.; the greatest thickness (from side to side) 8.5 mm.;... But
exactly in these places, where the obvious thickness would destroy the re-
semblance to a leaf, the whole effect of the roundness is neutralized by the
increasing lightness of these parts—a lightness which is so disposed as to
just compensate for the shadow by which alone we judge of the roundness of
small objects. (Much larger objects can be judged of by the change of
focus, which becomes necessary as their near or distant parts are observed.)
In shading the drawing of an object so as to represent roundness, the shade
is made to become gradually less and less deep as the tangential planes repre-
sented come nearer and nearer to a right angle with the axis of vision. So
here, the converse of shading—the whiteness neutralizing the shadow which
shading is intended to represent—dies off gradually as the (representation of
the) mid-rib is approached.

“The whiteness is produced by the relative abundance of white dots and
a fine white marking of the surface which is present everywhere, mingled with

the green. The effect is, in fact, produced by a process exactly analogous
to stippling.

“*By this beautiful and simple method a pupa, which is 8.5 mm. from
side to side in its thickest part, appears flat and offers the most remarkable

resemblance to a leaf which is a small fraction of 1 mm. in thickness.’ ”’

CHAPTER II

DEFINITION OF TERMS. ILLUSTRATIONS OF OBLITERATIVE COLORATION

EFORE going further we must clearly establish and define the special
descriptive terms which are to be used in the course of the book.

The term, ‘‘the law which underlies protective coloration,” as applied to
counter shading, was inexact, since ‘‘ Protective Coloration” of course includes
not only concealing-colors based on this newly disclosed principle, but many
branches of the entirely different principle of Mimicry, as well.* A name
even more to our present purpose than Protective Coloration, for the com-
prehensive meaning, would be one which should include all modifications of
the bodies of animals, both those of form and those of color, whose ob-
ject seems to be visual deception of any kind. This would make room for
offensive as well as defensive mimetic resemblances, etc., and for the many
curious cases of protective form modification, most common among the lower
orders of animals. But we are to have so little to do with these partially
extraneous principles that we need not discard the old and familiar term, Pro-
tective Coloration. Interchangeably with it, however, we shall use others some-
what more comprehensive, viz., Disguising Coloration and Disguising Costumes.

* Throughout our book we shall use the word Mimicry in a wider and perhaps looser sense
than that in established use among zodlogists, and we herewith offer an apology for this innovation.
In order to emphasize tersely the fundamental difference between ‘Obliterative Coloration’ and
both the principles involving imitation of definite objects, which principles have been known re-
spectively as Mimicry and Protective Resemblance, we have found it necessary to join the two last
mentioned under the general head of Mimicry. Derivatively, the name is nearly as applicable to
one as to the other, and the limiting it to the simulation of the colors and forms of animate creatures
by those of other animate creatures, in contradistinction to the imitation of inanimate objects, is more
or less arbitrary. The two phases are closely related, and for our present purposes must be consid-
ered as different branches of one principle, which can only be called Mimicry.

Fic. 1. Two bird-models, just
alike cxcept that the one on the left
is counter-shaded, the other’ not,
though covered uniformly with the
very iaterial of its background.
This right-hand model, therefore,
is actually as light below as above.

Fie, 3.

ie, 2. Obliteratively-shaded bird-model,
as in Fig. 1A, but inverted. (Somewhat
side-lighted, )

Fic. 4. Two hird-models as in Fig. 1, but out of doors against
bare ground. The one ou the right is obliteratively-shaded, the
other not,

Fic. 5. Two bird-models precisely as above save that the
right hand one is still better ‘obliterated.’ The reader will
have to take it on faith that this isa genuine photograph, and
that there 7s a right-hand model of the same size as the other,
unless he can detect its position by its faint visibility in Fig. 4.

Bird-models as in Fig. 1,
but with the top-light eut off from
the obliteratively-shaded one, A.

Protective or Disguising Coloration, then, as we define it, falls into two
main divisions; the one including concealing-colors mainly based on counter
shading, and the other including Mimicry, in almost all its branches. As
has already been explained, the goal of the former principle is the rendering
animals invisible in their normal haunts. Mimicry, on the other hand, aims
at deceptive visibility; it makes an animal look like something else than what it
really is. It will be seen that the latter principle is open to unlimited varia-
tions of method and result, whereas the former, as we have proved, is in its
main essentials strictly limited. ‘There are innumerable kinds of solid objects
for animals to simulate in appearance, but there is only one way to make a
solid object in a natural lighting cease to appear to exist. Both these are
principles of disguising costume, and both are protective, yet they are funda-
mentally unlike. It becomes necessary to find a fully adequate name for the
stricter principle—a name less technical and more explicit than “counter
gradation.” Obliterative Coloration is a phrase that will fit the general
principle, and Obliterative or Counter Shading may be used as a stricter term
for the essential root of it.

We have, then, Obliterative Coloration, and Mimicry, as the two main prin-
ciples of Protective Coloration. Of the well-known and well-studied prin-
ciple of Mimicry, we shall give but few examples, and these chiefly from
among the lower orders. In the higher orders, it seems, as we have said, to
play a very insignificant part.

Figs. 1-5 illustrate obliterative shading, pure and simple. Fig. 1 shows
an obliteratively shaded artificial model, contrasted with a monochrome one
which is colored precisely like the background, being covered with the very
same material; Fig. 2 shows a counter-shaded model inverted, and Fig. 3
the two models in the proper position, but with the direct top-light cut off
from the counter-shaded one.

Fig. 6 shows a Barred Plymouth Rock hen, a bird which completely lacks
obliterative shading, photographed, out of doors, against a background made
wholly of the flat skins of similar hens. A more striking demonstration of

the powerlessness of mere similar colors to conceal could hardly be devised.
So, were it not for his obliterative shading, would the leopard or jaguar show
up in the forest, despite his richly spotted forest-pattern.

Fig. 7 shows a pure white hen, photographed against a white cloth, an-
other illustration of the ineffectuality of mere color-resemblance. The hen
is conspicuously solid, her back showing light and her belly dark against the
flat white plane of the cloth. Every part of her surface, in fact, except for a
few mere points of transition, is either too dark or too light to match her back-
ground. A ptarmigan in winter plumage lacks the advantage of counter
shading, and must needs lack it, since even the middle of its back has to be
white to match its pure white snowy background,-and nature can furnish
nothing Jighter than white feathers for the bird’s underside. But the up-
ward reflection from the snow itself goes far toward canceling the shadow
on such animals. (See Figs. 8-10.) In the same way the reflection from
bright sand codperates with the delicate counter shading of desert animals,
which are usually very light colored. Such creatures are also as a rule al-
most unmarked, and thus furnish good examples of the use of obliterative
shading, pure and simple. It is on a delicate scale, however, since there is
but a short range of shade between pure white and the delicate brown re-
quired to make the animals’ backs ‘coalesce’ with the sand. Desert animals
are of course habitually exposed to full sunlight, but the excess of shadow
which the undersides of sunlit animals normally bear,* is in this case almost
or quite counteracted by the light-reflecting power of the bright desert sand.
Many forest animals, on the other hand, wear a slight counter shading at the
dark end of the scale—that is, from some dark color to a very slightly lighter
tone—because of the extreme diffuseness of the light in shady forest recesses,
whose colors are mainly dark and rich. The need of extreme counter shading
—from very dark to purest white—seems restricted mainly to high-standing
animals which live in the open on dark ground. On such a one the direct
sky-light makes its full graduated shading, and the shadow of the undersides

*See p. 18, Chapter I.
26

Fic. 6. Plymouth Rock hen—a bird which lacks counter-shading—against a flat background of
Plymouth Rock hen skins, demonstrating the same thing as Fig. 7.
Photographed from life.

Fi. 7. White fowl, lacking counter-shading, against a flat white cloth rome
object can not be ‘obliterated,’ no matter what its Clemuad: CE Se eee

Photographed from life.

i
¥
4 j
hy y
4
Lot
Fic. 8 Rocky Mountain White-tailed
att in winter plumage, on snow, and
favorably lighted for inconspicuousness.
Rotundity as dimly apparent as is possible ri

without counter-shading.

Photographed from life by Edward R. Warren.

Fic. 9, Rocky Mountain White-tailed Ptarmigan, in winter plu-
mage, off snow. Their rotundity, revealed by their lack of counter-
shading, ismarked. But they may still pass for lumps of snow.

Photographed from life by E. R. Warren.

Fic. 10. Rocky Mountain White-tailed Ptarmigan in winter plumage, on snow, but
unfavorably lighted for inconspicuousness. :
Photographed from life by E. R. Warren.

is not alleviated by upward reflection; while the highly illuminated back has
to be of a very dark tone to coalesce with the dark earth, rock, or whatever
it may be that forms the animal’s normal background.

These examples serve to illustrate the law, almost or quite infallible, that
the range and scale of an obliteratively colored animal’s counter shading de-
pend on the ratio of the average brightness above it to the average darkness
beneath it, in its normal haunts. Thus, to recapitulate, we find on sandy
deserts birds, mammals, and reptiles counter-shaded from sand-color to
white, while on dark-colored open ground we find them shaded from very
dark to white. (Of this last class the smaller Wood Sandpipers (Totanus),
which live on muddy stream and pond banks, are excellent examples. So
also, in a cruder form, are some of the Oyster-catchers (H@matopus) and
Stilts (Himantopus), whose counter shading consists of two tones only, black
and white. Among mammals, examples are the darker-backed hares, deer,
kangaroos, etc., which live more or less fully exposed to the sky-light on rather
dark ground.) Where the sky-light is intercepted and diffused by foliage or
other natural obstructions, as on the ground under grasses, bushes, etc., on
marsh-land under reeds and rushes, and, most of all, in the forest, we find
many rich or dark-colored animals with a weak obliterative shading (one,
namely, whose bright climax comes more or less short of white, being even in
some cases but slightly lighter than the tone of the back). Many of the for-
est-inhabiting passerine birds of Europe and America wear this form of coun-
ter shading, as do also certain forest grouse, as well as squirrels and other
mammals; while among tropical birds it is well represented by many green
parrots and parrakeets, etc., and also by many brown species that inhabit the
gloomy interiors of the great forests. Some of the ground sparrows, and the
rails, are good examples of the grass and swamp forms, while the female of
the European Blackbird (Merula), and the North American Catbird (Galeo-
scoptes) may be cited as examples of the thicket-haunting form among fa-
miliar birds. This indisputable fact, that animals tend to be dark in thickets
and dusky forests, and pale on the glaring desert, and on ocean beaches, is a

complete refutation of the theory that the counter shading is due to the tan-
ning effect of light. On the other hand, the idea that the paleness of desert
creatures is due to bleaching, is equally well answered by the fact that their
shadowed undersides are still the lightest, as in the case of almost all other
animals.

Figs. 11-13 show photographs of the skins of various birds and mammals,
split longitudinally through the lower median line, and spread out flat. This
is a simple and adequate way of exhibiting the exact character of the obliter-
ative shading of animals. The names of the species thus represented are
given under the pictures. It will be seen that some beasts which are usually
considered practically monochrome, such as the Mink (Putorius vison), have
in reality a slight counter shading. (See footnote, p. 123.)

Pictures of protectively colored wild birds and mammals in situ cannot be
really true to Nature if they represent them as having the light-and-shade of
normal solid objects—a fault usually committed by illustrators, who study
them in unnatural situations, such as the cages of a menagerie, or other places
where the illumination fails to codperate with their counter shading. These
paintings of ours (grouse, rabbit, snake, caterpillars, etc.) are intended as
examples (outside the field of photography) of trwe animal illustration—ren-
dering instead of defeating the wonderful obliterative effects of their counter
shading.* .

Of course so new a lesson cannot be learned all at once by the world at
large. But when the truth on any subject has once been started, it cannot
fail gradually to supplant the previously existing errors. It will be many

* Japanese and Chinese art almost entirely dispenses with light and shade, dealing solely with
line and color. Japanese pictures of birds and mammals, therefore, represent, approximately, the
animal’s actual color tones, quite irrespective of shading. A white belly, for instance, is painted as
bright as a white back. Thus these Oriental renderings of animals are actually, in one sense, more
realistic than the Occidental, because by their complete lack of shading they approximate the won-
derfully unsubstantial look of the birds and beasts in Nature. An object which shows lighter on its
lower border than its upper, under the light of the sky, cannot possibly look solid. It looks at most
like a party-colored flat (or concave) surface, rather than a rotund body.

Fie. 11.

Fie. 12.

Fies. 11 and 12, Mammals’
skins spread out to show oblit-
erative-shading.

Fic. 11. Spotted Seal (Phoca
vitulina.)

Fie. 12. Cotton-tail Rabbit
\Zavus floridanus transitionalis. )
[Cf above.]

Fic, 18, Birds’ and mammals’ skins spread out to show obliterative-shading, continued. The
species are as follows: Beginning above, left, Blue Jay (Cyanocitta cristata), Tree Swallow (Tachycinetia
bicolor), Pine Grosbeak (Pinicol leat densis, female), Common Chipmunk (Tamias striatus)
Mink (Putorius vison), English Sparrow (Passer domesticus, female), Lesser Whitethroat (Sylvia cur
TUCH) , two kinds of shrew-mole, names (?) jumping mouse (Zapus hudsonius, stuffed skin, side view)
Am, Siskin (Spinus pinus), Gray Squirrel (Sciwrus carolinensis), Muskrat (Fiber zibethicus) and sharp—
shinned Hawk (Aceipiter velox, young female).

years, no doubt, before a drawing with conspicuous light-and-shade of a live
sandpiper or rabbit in Nature is looked upon as an absurdity—and yet that
time must surely come.

Having considered obliterative shading, pure and simple, we will now
advance to the next stage in the study of obliterative coloration, namely, the
use of markings on counter-shaded animals.

The first few chapters will deal chiefly with artificial models.

CHAPTER III

FIRST PRINCIPLES OF THE USE OF MARKINGS WITH OBLITERATIVE SHADING

HE need of markings is a natural concomitant of the principle of ob-
literative shading. When an unmarked solid object in a given lighting
has been reduced to a perfectly ‘flat? monochrome by counter shading, so
that it lacks all visible attributes of solidity, it may be quite undistinguishable,
provided that its background is of a similar monochrome flat tint. Such is the
case in Fig. 14. The solid model is almost undistinguishable, seeming merged
into the flat plane of the cloth-covered board, which in reality is several yards
behind it.

Complete ‘obliteration’ has taken place; for the model, having no dis-
tinctive light-and-shade, color, or surface character, is as it were absorbed
into its background, and the space in which it stands seems occupied by empty
air. But if we now apply a pattern to the background, as in Fig. 15, the case
is changed. Though still unsubstantial-looking, and very inconspicuous, the
model is clearly discernible as an interruption of the background-pattern. If
this pattern is small and regular, as in our figure, the whole of the unmarked
object’s characteristic outline may be traced against it, and by the process of
mental inference already alluded to, the observer will recognize it, in spite of
its ghostly flatness, as a solid body between him and the background-plane.
But behold the effect of applying a like pattern to the model also, as in Fig.
16! It immediately recedes again into the flat plane, and the eye loses it even
more surely than before, because its likeness to its background is now positive
and graphic, at many points.

The foregoing figures illustrate the simplest form of the use of markings
in codperation with obliterative shading. The next thing for us to consider

Fig. 14, Obliteratively-shaded bird-shaped
model against plain background, (Defective
photograph, retouched. The model might
show even less, in reality. Cf. Iigs. 4-5.)

Fic. 17. Spotted, obliteratively-shaded
bird-model, as in Fig. 16, but wrongly
lighted. ‘his picture shows the depeni/-
ence of the part played by pattern in the
obliteration of leopards, zebras, etc.
Without counter-shading, these animals
would look conspicuously solid, despite
their patterns.

Fic. 15. Bird-shaped solid model,
obliteratively-shaded in full, and
correctly lighted, but revealed by its
blank silhouette against a spotted
background.

Photograph.

16._ Bird-shaped, oblitera-
haded model, as in Fig. 15,
but concealed by the addition of
sputs like those of its background.
Photograph.

is the matter of pattern perspective. The elucidation of this will mark another
step in the differentiation of obliterative coloration from all forms of mimicry.
For it will show that not an exact reproduction of the actual background-
pattern, but a picture of that pattern as it looks when more or less altered and
refined by distance, is essential to the concealing of an object. Or, in other
words, ‘that the object’s obliteratively-shaded surface must bear a picture of
such background as would be seen through it ij it were transparent. The
diagram, Fig. 18, represents a flat, bird-shaped model, vertically placed,
seen against a horizontal background. The background-pattern is supposed
to be actually uniform throughout, but diminished to the eye as it recedes on
the horizontal plane. The model, vertically interposed between the eye and
this receding ground-plahe, must, for concealment, bear a pattern graduated
from larger on its lower borders to smaller on its upper. For the highest
parts of the model are seen against the most distant and therefore most dimin-
ished portion of the uniform background-pattern—and vice versa. Further-
more, the markings of the background, being on a receding plane, are jore-
shortened throughout, and this effect also must be imitated on the model.
These diagrams and photographs will serve to illustrate, in a crudely sim-
plified form, some of the main principles of obliterative pattern which prevail
in Nature. Instead of one unvaried pattern on a single plane, however, Nature
furnishes backgrounds of rich diversity. Mud, grasses, pebbles, bushes, tree-
trunks, branches, leaves, living and dead, and vistas amid vegetation to the
bright sky beyond—these, all of them subject to endless variations of com-
minglement, of distance, and of lighting, are a few of the numberless details
of the backgrounds against which ground-haunting animals are seen. To
achieve the highest degree of inconspicuousness, these animals must wear,
superadded to their obliterative shading, yet in the main conforming with it, a
sort of compound picture of their normal backgrounds—a picture seemingly
made up by the averaging of innumerable landscapes. Further, this land-
scape-picturing must be suited variously to different portions of the animal’s
surface. The top-planes, being seen in full only against the nearer ground,

must bear a larger pattern than the sides (see the second diagram, Fig. 19),
which are seen against more distant ground or forest landscape, with details
reduced and altered by perspective; and the highest portions of the side-planes,
e. g., the sides of the animal’s head, being seen, in the long run, against the
most distant backgrounds, must have the finest pattern of all. Codperant
with these principles is the fact that the pattern looks different on receding
planes of the solid object. Thus in the side view all that shows of the neces-
sarily coarser top-pattern is so refined and narrowed by perspective that it is
fully equivalent to the actually finer pattern of the sides. In the reverse case,
the side-pattern scarcely shows at all.

Nature’s achievement of this ultimate perfection of obliterative coloration,
on birds, is the subject of our next chapters.

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Fic. 19. Diagram supplementing Fig, 18, showing the
coarser back-pattern, required to match the ground-
pattern un-foreshortened and almost undiminished, as
when seen from directly above.

Fig. 18. Diagram showing the punarny of perspective by animals’
patterns. The hird is supposed to he vertically placed, and looked some-
what down upon against a uniformly patterned horizontal ground-plane.

Fic. 21. Shows particularly well the head-markings’
picturing of a shadowed cavity crossed by lighted twigs
or grasses.

eerie 20-21. American Woodcock on its nest; showing the working of the wonderful obliterative picture-patterns, founded on counter-

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CHAPTER IV

BACKGROUND-PICTURING ON OBLITERATIVELY-SHADED BIRDS. FIRST TYPE,
PICTURING OF THE LARGER DETAILS OF THE NEARER GROUND, ON
TERRESTRIAL BIRDS

EREWITH we leave the arid field’ of demonstration with artificial
models, and launch into the wonderland of actual Nature. If we
compare the numerous cases of evident background-picturing on the bodies
of obliteratively-shaded birds, we find that they are clearly separable into
several main classes or divisions. Many of the species, for instance, have a
wonderfully minute and intricate pattern, while others, almost equally famous
for their ‘invisibility,’ are marked in a much simpler and more blotchy
way. The finely-patterned class is again divisible into two very different
‘branches, as we shall see later on. This chapter, as the heading indicates,
is to be devoted to the more blotchily-marked type of pattern-bearing ‘In-
visibles.’ The best examples of this type are terrestrial birds which live
among fallen leaves and sticks, etc., or among weeds and grasses, patches of
mud, and pools of water. Preéminent among them are the Snipes and
Woodcocks (Philohela, Gallinago, etc.),—Figs. 20-26.

The American Woodcock (Philohela minor) is a beautiful representative
of the class. See Figs. 20-22, reproduced from photographs of live Wood-
cocks in Nature, and Figs. 23-24, which show photographs of a dead Wood-
cock against a normal background, but with its obliterative shading variously
upset. In Fig. 24A, the bird is on its side, with its back toward the spectator.
Thus the largest expanse of its pattern is exposed to view, yet it completely
fails to obliterate, chiefly because it is no longer aided by a proper light-and-
shade gradation. Fig. 24B shows the same bird with wnder instead of upper
side exposed—in which position it is of course even more conspicuous. Fig.

23 shows the bird, with the general shade of its back artificially extended over
its sides and belly, posed to simulate as nearly as possible the attitude of the .
live bird on its nest represented in Fig. 22. The contrast between the two,
as to conspicuousness, is most pronounced.*

No clearer elucidation could be devised of the pattern-principle in ques-
tion than is furnished by the photographs of live Woodcock and Snipe (Figs.
20-22 and 25-26). The imitation of the larger details of the squatting
bird’s near background is exquisitely perfect, particularly. in Figs. 22 and
25. Dead leaves, twigs, and grasses, variously disposed over shadow-holes,
in a near view, are the main components of the pattern-pictures which
such birds wear. Because they are strictly terrestrial and rather sedentary,
in time of danger usually squatting motionless on the ground, and allowing
enemies to approach them very closely before they fly, they are almost always
seen against a comparatively near portion of the ground-plane, and hardly
ever against a highly diversified forest landscape. Hence a picturing in
slight reduction of the simpler ground-pattern of leaves and twigs, etc., com-
mon to all the bogs and coverts which these birds inhabit, is all that is needed
for the complete ‘obliteration’ of their counter-shaded bodies.

Many other examples of this class of background-picturing could be cited,
but the ones already given will suffice. That most beautifully patterned bird,
the European Woodcock (Scolopax rusticola), belongs in a distinctly different
class, and will be considered later on.

* These four pictures (Figs. 22-24B) are reproduced from the article in the Awk mentioned in
our preface.

Fic. 25. Wilson’s Snipe on its nest; ‘obliterated’ by counter-shading and
Biome pattern (representing sticks, grasses, etc., with their shadows, at various
istances. )
Photographed from life by Herbert K, Job.
Here reproduced by courtesy of Houghton, Mifflin & Co.

Fic. 26. Jack Snipe (Gallinago caelestis.) Still more specialized ‘picturing’ of straich ight stick
dead reed stems, or broad grass-blades) and shadows, [Cf. the Chipainnk Figs iB and o3) © Se ae

Photographed from life by Cherry and Richard Kearton.
Courtesy also of Cassell & Co.

Fic. 27. Nesting Whip-poor-will. [Cf. Fig. 28.]
Photographed from life by Herbert K. Job.

Fic. 28. Whip-poor-will (Antrostomus vociferus) on its nest. Near-ground-‘picturing’ patterns of the minutest type,
founded, as always, on obliterative shading.
Photographed from life by Rett E. Olmetead.

CHAPTER V

BACKGROUND-PICTURING ON OBLITERATIVELY SHADED BIRDS, CONTINUED.
SECOND TYPE,—INTENSELY ELABORATE PICTURING OF THE MINUTE
DETAILS OF THE NEAR GROUND, ON TERRESTRIAL BIRDS

HERE are two main types of intricate-pattern background-picturing,

as there are two classes of minute forms and markings in field and

forest landscape. The one consists of the actually minute markings of the

various inanimate objects, such as leaves, logs, sticks, stones, grasses, etc.,

seen at very close range; and the other of the cruder forms of large objects and

groups of objects, such as tree-trunks and branches, and sky-vistas, reduced
and refined by distance into a delicate pattern.

Marvelously fine and intricate patterns, rendering with almost microscopic
minuteness the aspect of dead leaf and mossy log surfaces, seen at extremely
close range, with an admixture of somewhat more distant ground-vista pictur-
ing, are worn by such birds as the terrestrial forest Goatsuckers (Caprimulgide),
which are almost: unique among birds in their evident extreme dependence
on obliterative coloration. Squatting motionless on or near the ground in
the depths of shady forests, they take wing only as a last resort, when almost
trodden upon by an enemy. In conformity with this habit, their obliterative
pattern is developed to a point of minutely detailed realism quite beyond
that of such well-concealed ground birds even as the American Woodcock.
It is as if the Woodcock wore an adequately true facsimile of the main effect
of its dead leaf and stick background, with the smaller markings of these ob-
jects largely omitted, while the Goatsucker wears a similar pattern-picture
carried out to the last degree of finish, with all possible minute details faith-
fully represented. The intricate bark- and lichen-pattern of the surface of a
fallen log, the reticulations of dead leaves,—all the innumerable delicate mark-

ings discernible upon close scrutiny of the forest ground, together with the
larger pattern formed by groups of slightly more distant leaves and twigs, etc.,
with their high-lights, their middle tones, and their dark shadows,—all these
things, variously reduced by perspective, are clearly suggested to an appreci-
ative observer by the marvelous patterns of the forest Caprimulgide. The
fact that none of these detail-picturings is so patently realistic as to be appreci-
able to everyone when the bird is seen away from its natural environment, is
part of the very marvel of the thing. Thanks to some process * which in its
visible results has amounted to something like an averaging of all the normal
backgrounds, against which, from aboriginal times, the animals have been
seen, they bear a pattern precisely similar to none, yet amply fitting all. This
effect of perfect averaging or compounding is one of the most beautiful and es-
sential parts of the obliterative principle. (In certain cases, which will be
considered later on, an animal’s background is subject to so little variation
that a more simple and single imitation of absolute details is possible.)
Though fully developed, the obliterative shading underlying this pattern-
system of the goatsuckers is slight in range, conformably to the diffuseness
of the top-light in deeply shaded woods, which these birds inhabit during
the day. True obliterative coloration perhaps makes its nearest approach
to mimicry among animals bearing this form of pattern. For while the coun-
ter shading as well as the character of the markings proves the case to be one
of obliteration, or merging with the background, yet the apparent extreme
nearness of some of the pictured details, which in certain views will even ‘co-
alesce’ perfectly with the markings of the very object on which the animal is
sitting, such as a stone or mossy log, gives the phenomenon, in part, close
kinship with the exact mimicry of surface-detail on an animal whose protec-
tion is the simulation, with full appearance of solidity, of a single inanimate
object. It is furthermore undeniable that a finely-patterned bird such as we
have been describing does occasionally pass for an excrescence of the log or
rock on which it sits. This may be the case, for instance, when it is seen in

* We ourselves attribute all such work to natural selection, pure and simple and omnipotent.

Fic. 29. Nighthawk—a percher in the open, on lichen-
freckled rocks, tree boughs, etc. Near-ground-picturing of the
minutest type (based, of course, on obliterative shading.)

Photographed from life by J. E. Seebold.

Fic. 30. Nesting Nighthawk. ([Cf. Fig. 29.]
Photographed from life by Ora K. Knight.

Fic. 31. Ruffed Grouse walking. ‘Obliterated’ by its highly-
wrought picture-pattern, based on complete obliterative shading.
Photographed from life by James R. Miller.

Fic, 32, Nesting female Ruffed Grouse.
Photographed from life by James R. Miller.

full side-contour against an unfavorable background, especially if its mark-
ings do not clearly show. For, we repeat, these markings, though pictures
of comparatively near details, are still pictures, in the sense of representations
of patterns beyond the animal, and not exact facsimiles of the surface-mark-
ings of any object. It must be remembered that a large class of the enemies
of such a bird, namely, the terrestrial carnivorous quadrupeds, which ap-
proach it on its own level, usually see it against a more distant background
than do we tall bipeds who look down upon it. In accordance with this fact,
it will be found that there is more than one would at first suppose of the ele-
ment of distant background picturing in the side-markings of most terrestrial
birds. But even if it is merely the thickness of an animal’s counter-shaded
body which habitually intervenes between its exposed side and the seeming
background pictured by its markings, the principle is not mimetic, according
to our nomenclature. To complete the statement, we must add that no ani-
mal bearing. a full obliterative shading can, under normal conditions, pass for
some other kind of solid object, but must appear either as a flat plane, or as
merged into the scene behind it, whether near or far,—the smallest possible
extent of its apparent retrocession being a distance corresponding to the thick-
ness of its own body; but in order that it may completely undergo such ‘ob-
literation’ the pattern which it wears must always be smaller than the actual
pattern of its background.
Figs. 27-30 need no explaining in the text.

CHAPTER VI

BACKGROUND-PICTURING ON COUNTER-SHADED BIRDS, CONTINUED. THIRD
TYPE,—-PICTURING OF THE MORE DISTANT BACKGROUND ON PARTIALLY
ARBOREAL BIRDS

T is obvious that high-standing and tree-perching birds tend to have more
distant ‘backgrounds’ than do those that squat on the ground, and that
in many cases the only pattern which could adequately codperate with their
obliterative shading would be one which should ‘coalesce’ with a highly diver-
sified forest-interior landscape. A landscape, that is, made up of tree trunks
and branches, near and distant, the interminably various criss-cross pattern
of the smaller twigs, stretches of sunlight-dappled ground, glimpses of sky,
etc.,—or, in other words, the second type of intricate pattern named in the
preceding chapter.

Such a pattern exists on many birds, and when, as in nearly all the cases,
it is to some degree commingled with a representation of the nearer details of
the ground-plane, to suit its wearer’s partially terrestrial habits, it marks the
very consummation of the obliterative principle. Certain forest grouse,
such as the Bonasa umbellus or Ruffed Grouse of North America, and the
Hazel Grouse (Bonasa betulina), of Europe, are perfect examples of this type.
The colored plate represents a cock Ruffed Grouse, against a variegated forest
interior. ‘This picture, as stated in the Preface, was painted from woodland
photographs, etc., and from a stuffed grouse in a house-lighting artificially
arranged to suit the bird’s counter shading. Notice his complete lack of
light-and-shade indicative of solidity—by which lack his beautiful ground-
and-forest markings are enabled to ‘coalesce’ effectively with those of his back-
ground. Such—or even more magically obscure—is the aspect of a live
Ruffed Grouse in a naked tree, which the eye of the hunter scans in vain at-

EXPLANATION OF PLATE II

MALE RUFFED’ GROUSE IN THE FOREST.

Painted by Geral

Sli

Ski GEE Te

PLATE II

ANOEN 8:00. BALUMORE .

tempt to detect its ghostly form. The bird is in plain sight, but invisible—
such is the wonderful power of full obliterative coloration. Nature has, as
it were, used the bird’s visually unsubstantialized body as a canvas on which
to paint a forest vista. In this there is nothing of mimicry, as we define it.
Mimicry uses the solid aspect of an animal’s body, modified in form and color,
to simulate some other solid object. But vista- or background-picturing,
based on the complete obliteration of the animal’s solid aspect, which causes
its actual form to pass for an empty space, is a widely different principle.
Even in the terrestrial moments of the Ruffed Grouse’s life, it is usually seen
against more distant backgrounds than are the Goatsucker and Woodcock,
because it largely lacks the squatting-habit, except in the case of the young,
or the female sitting on her eggs. (See Figs. 31-33.) Noteworthy in this
connection is the fact that the markings of the sexes are decidedly unlike. In
the female, the most critical portion of whose life is probably the annual three
weeks’ brooding on her ground nest, the blotchy near-ground pattern pre-
dominates over the forest-vista pattern; whereas in the male it is just the
other way. It is difficult or impossible to distinguish the two styles of pattern
absolutely in either case. But they are so adequately commingled, in one or
the other predominance, that, however the bird is placed, some portion is
almost certain to coalesce perfectly with its background; and with this key-
note of complete obliteration the remainder of the pattern amply serves its
purpose. Indeed, not even this degree of actual immediate ‘matching’ is
necessary for the bird’s concealment. His costume is a sort of patchwork of
pictures, subtly intermingled, each an epitome of some particular type or
detail of woodland scenery. Such details and bits of landscape are charac-
teristic of the place in general, and even when those furnished by the grouse’s
pattern are unmatched by any in his immediate background he is not apt to
be revealed. Only an artist, perhaps, can rightly appreciate the profound
and perfect realism of these background-pictures worn by birds and other
animals. Just as a good caricature drawing of a man looks in one sense
more like the man than the man himself, so, in a far more high and wonderful

degree, do these pictures on animals’ coats exceed the verisimilitude of the
actual scenes they imitate. They have been compounded and epitomized
and clarified till only pure, essential typicality remains. The difference may
be stated tersely thus: On the one hand, we see a stick, a leaf, a web of twigs
over the sky; on the other hand, we see stick, leaj, web of twigs over sky. Just

as in great human art, but far more essentially and surely, the trivialities
"and chance individual abnormalities have been eliminated, or subordinated
to the scheme of ultimate, impartial typicality. To learn, then, the purely
characteristic colors and light-and-shade effects of leaves and sticks and
stones and other parts and types of natural scenery, we should look not at the
scenes themselves, but at the animals whose patterns picture them. The
essential realism of these pictures is such as the keenest artist among men
could never hope to match. Nay, for Nature herself has made them—Nature
herself has discovered and applied, to a point utterly beyond human emula-
tion, the art of painting pictures.

Let us recur once more to the Ruffed Grouse. The transverse barring
of its breast and flanks, a form of marking common to a majority of the larger
birds inhabiting northern forests, closely imitates the appearance of hori-
zontal branches seen at rather short range. Such branches are a very im-
portant feature of coniferous forest scenes. When this barring occurs on
the underside of a forest bird, it is almost invariably continued by a series of
spots on the outer webs of the primary wing-feathers. These spots become
confluent when the wing is folded, and thus the large-branch-picturing is
made to extend almost uninterruptedly across the bird. (See the colored
plate. Our grouse, however, was rather weakly barred underneath.) The
beautiful oval-spotted pattern of the Ruffed Grouse’s rump is somewhat hard
to analyze. It plays a small part in the side views, but has great prominence
when the bird is seen from above. More than anything else, perhaps, it
looks like a several yards distant patch of pine-needle-covered ground, peppered
with small dead leaves, such as those of the Checkerberry (Gaultheria), or
dappled with broken flecks of sunlight.

Fic. 33. Ruffed Grouse brooding. This
picture admirably illustrates a phase of
ground-matching by the Ruffed Grouse’s
most beautiful and elaborate ‘obliterative’
picture-patterns.

Photographed from life by George C. Embody.

Fies. 34-35. Dead Ruffed Grouse laid on its side. Fig. 34, breast view; Fig, 35, back view
because in wrong positions for the normal working of the obliterative shading,
Photographed out of doors.

; both conspicuous

Fic. 36, Two photographs of the same piece of a Great Horned Owl’s wing, super-imposed on a photograph of white
pine woods, to show how closely the owl’s patterns reproduce such a forest-interior.

It is to be remembered that aside from the nesting ordeal, the Ruffed
Grouse’s greatest need of protection is in the autumn and winter, when many
of the trees are leafless. Deep wood interiors are more or less brown, even
in summer, and, above the ground, in winter likewise, so that a grouse’s colors
are never really out of harmony with its environment; but it is in the two
brown, leafless seasons between green summer and white winter that the
average likeness between bird and landscape is the closest. During the
snowy winter months the Ruffed Grouse becomes more largely arboreal,
climbing about among the smaller branches of deciduous trees, with almost
the agility’of a parrot or crossbill, picking buds—which are its principal food
at this season. Forest vistas above the ground, with the intricately striate
pattern of small, naked twigs, are therefore among its commonest winter
backgrounds, and a large element of its pattern fits these scenes to perfection.

Another bird which wears a highly developed forest-vista pattern is the
American Great Horned Owl (Bubo virginianus). This owl sits nearly
erect in deep woods, and its obliterative shading is proportionately slight.
Horizontal-branch-barrings are the chief pattern of its underside, while its
back and particularly its wing-coverts bear a beautifully suggestive picturing
of variously extended vistas through the twigs and tree trunks. (See Fig. 36.)
The white breast-mark looks like a sky vista, or some other large, light-colored
detail of the woodland scene. It belongs among.contour-breaking ‘ruptive’
markings (see Chapter XIII, pp. 77-78) and among those which ‘let in’ the
sky (chapter XXII, p. 149, etc.).

The great European Eagle Owl (Bubo maximus) is almost the counter-
part of B. virginianus in coloration, but somewhat more boldly and sparsely
marked, in accordance with its less strictly sylvan life.

The Great Gray or Lapp Owl (Scoptiaptex cinereum and S. cinereum lap-
ponicum), an inhabitant of dense fir and spruce forests in the far north of both
continents, wears a congested but little diversified pattern strongly suggestive
of the dusky recesses of these northern woods. Most beautiful of all is the
forest-picturing on the little Screech Owl (Megascops asio) of North America.

As is well known, there are two perfectly distinct color-phases of this owl,
the red and the gray. It is in the gray plumage that the forest-pictures are
most highly developed. Largely confined to this phase, also, is the curious
defensive habit of sitting sharply erect, raising the ear tufts straight upward,
closing the eyes to narrow diagonal slits, and drawing the feathers so close
to the body that the usually fluffy bird is reduced to about one third its ordinary
thickness. Of this interesting performance only one explanation, and one
which long seemed sufficient, has been forthcoming. People have supposed
that the owl practices protective mimicry, by assuming the aspect of a stick or
stub. While it is not to be doubted that such a purpose is often served, in
part, at least, yet the fact that the bird has counter shading—which even in the
nearly erect position tends to ‘obliterate’ it, and to make it look unlike a stick
—together with the very evident forest-vista character of its pattern, goes far
toward proving that mimicry is not the only object of the trick. The grotesque
contraction serves also to bring the background-pictures to their clearest and
sharpest. The more tightly and closely a bird’s feathers are laid against its
body, the clearer do all its markings become. The Ruffed Grouse has a like
habit—so have bitterns and many other obliteratively colored birds—and
in all these cases the action, whatever may be its other merits, is an essential
adjunct of the obliterative equipment. Since, by every token, these birds
are preéminently equipped for obliteration rather than for mimetic resemblance,
it seems likely that the contracting-trick has greatest value as a factor of
obliteration. On the other hand, it is undeniable that any such ‘contracted’
bird has moments of close mimetic likeness to a stick or stub. I shall return
to this question in a later chapter.

Judged by its markings, the European Woodcock (Scolo pace rusticola)
would seem to belong most decidedly to the ‘forest-vista-picturing’ class,
and such an opinion is largely vindicated by an examination of the bird’s
habits. It lives to a great extent in upland forest coverts, where its beautiful
and intricate wing- and side-pattern matches the vistas among trees and
stumps, with glimpses of mottled forest ground, while its barred breast matches

Fi, 37. Stuffed Long-eared Owl in white pine woods. [Cf. the next figure. } Fig. 38. Stuffed Long-eared Owl in mixed woods. Tree-twig-and vista-pictur-
Photograph. ing pattern (based, of course, on counter-shading.)
Photograph,

standing twigs and branches, and their shadows cast upon the ground. Many
other beautiful examples could be given of this type of forest-pattern among
birds.

The next chapter will treat of grass patterns, separated from the other
forms of near-background pattern which have already been considered because
of their involving slightly different principles.

‘CHAPTER VII

BACKGROUND-PICTURING ON COUNTER-SHADED BIRDS, CONTINUED. GRASS
AND HEATHER PATTERNS ON SPARROWS AND GALLINACEOUS BIRDS, ETC.

HE grass-pattern birds, of various orders, constitute a pretty clearly-
defined group in the obliteratively-patterned series. Generally speak-

ing, there is much less diversity in the backgrounds of terrestrial birds which
live in the open, than in those of forest birds, whether terrestrial or arboreal.
The ingredients of a field bird’s background are comparatively few and
simple, for the predominant vegetable forms of the open land are much less
diverse in size, and somewhat less in shape, than those of the forest. Further-
more, birds that are habitual dwellers on open ground—which, relatively to
the littered forest floor, lacks minor variations of level—are rarely seen against
anything but a very near background. Thus the possibility of their needing
the distance-picturing type of obliterative pattern (as described at the be-
ginning of Chapter VI) is largely eliminated. This comparative simplicity
of marking requirements would lead us to expect great uniformity in the
patterns of field birds; and investigation vindicates the supposition. Among
the birds which are wholly confined to open ground, either bare or grass-
grown, but which annually range over a wide territory, so that no one region’s
peculiar ground-forms could advantageously be pictured on them, there
exists a highly conventionalized ground-pattern of a fixed type, which is re-
markably little varied through several genera and families, even orders.
This type, always based on complete obliterative shading, is characterized
by striations of light brown and black, coarsest on the back, and more or
less varied by transverse bands and finer markings on the wings, scapular
feathers, and other portions. Birds which wear it are Larks (Alaudide)

Fic. 39. Rocky Mountain White-tailed Ptarmigan in transitional plumage,
against snow-brindled ground.
Photographed from life by Edward R. Warren.

Fic. 40. Rocky Mountain White-tailed Ptarmigan on her nest. Near- d-pi i spe “
course, ental oulerguveubadlag) [com 41, Uhape VLE) Sn as eae aE Ee ap ae a

Photographed from life by Evan Lewis.

Fre. 41. Rocky Mountain White-tailed Ptarmigan on her nest.
a very remarkable photograph.

Photographed from life by EB:

Fic. 42. Rocky Mountain White-tailed Ptarmigan among pebbles, rocks and grasses. (Female and chick.) [Cf. Figs. 39-41. ]
Photographed from life by Edward R. Warren.

Fic, 48. Sage Grouse (Centrocercus urophasianus), a ‘grass-patterned’
and ‘shadow-marked’ bird. - aS adie

Photographed from life by Edward R. Warren.

(almost all the species except the Shore Lark and its races), Pipits (Anthus),
certain European Warblers (Sylviine), various members of the Fringillide,
and some of the shore and moorland haunting Limicole, as the Curlews
(Numenius), and other Waders. Some of the more sedentary and local of
the migratory field birds, as for example, the North American Yellow-winged
Sparrow (Ammodramus savannarum passerinus) and the European Quail
(Coturnix communis), have developed more highly specialized patterns of a
very subtle nature,—patterns beautifully suggestive of the intricate small forms
of earth and grasses. But it is among the actually sedentary (i. e., non-migra-
tory) ground-birds of mountain moors and pastures, monotonous and little-
varied regions, where the forms of vegetable growth which cover the summer
ground are very limited in number, that the most simply specialized of back-
ground-pictures may be found. Such birds are the Ptarmigans (Lagopus),
already mentioned as preéminent among special-pattern birds. Living
always in exposed situations, and being much sought by many rapacious birds
and mammals, they are peculiarly dependent on protective coloration, at
all seasons. Almost all the species (the sole exception, as far as I know,
is the Scotch “Grouse,” Lagopus scoticus) turn white in winter, when their
boreal or alpine haunts are covered deep in snow. In spring and fall the
birds pass through a long intermediate stage, when they are curiously and
ever-varyingly pied with white and brown or gray. The fact that they are
thereby aided to escape detection on brown vernal ground mottled with
patches of melting snow, or on ground half dimmed with scanty autumnal-
snowfalls, might be considered nothing more than a coincidence, were it
not for the extraordinary slowness of the two seasonal color-changes. There
is perhaps no other bird which moults as gradually as the Ptarmigan, and this
fact goes very far to strengthen the supposition that it has developed a pecu-
liarly fluid and perfect system of perennial protective coloration. Figs.
8, 9, 10 and 39 show White-tailed Ptarmigans, of the Rocky Mountains, in
winter and transitional plumages. The photographs were taken from wild
birds in their native haunts. Supremely beautiful and potent is the grass-

pattern of this same species in summer plumage. See Figs. 4o and 41,
the second of which is one of the most remarkable photographs ever taken
of obliteratively colored birds in nature. Both photographs are of hen birds
on their nests. We have never been in the haunts of this ptarmigan, and
therefore cannot speak from personal experience as to the prevalence on
its breeding grounds of the strong, wiry grasses which form the brooding
bird’s background in these pictures, as well as in others not published here.
But the late Mr. Evan Lewis, of Idaho Springs, Col., who took the photo-
graphs, wrote us confirming our foregone conclusions as to the abundance
and general distribution of grasses of this type in the summer home of the
Southern White-tailed Ptarmigan. Indeed, an examination of the photographs
leaves one no room for doubt upon this score. So consummate a resemblance
could not be merely casual.

The principal feature of the pattern made by grasses over ground is a more
or less intricate lace-work of crisscrossing, light-colored, linear forms, some
straight, some curled and twisted, relieving with varying intensity against
dark. This pattern has the important attribute of simplicity, and is worn not
only by many birds and some frogs, but even by certain moths, which rest on
the ground during the daytime.* In the case of the ptarmigan, it is achieved
by light-brown marginal bands, with a few small internal spots, on the dark
feathers of the upper parts; the predominance of light and dark being grad-
ually reversed as the lower breast is approached. The belly is entirely white,
as are the quill feathers of the wings and tail. The white of both wings and
tail, however, is entirely hidden by grass-marked ‘coverts’ when the bird is
brooding. In addition to the phases already described, this bird has an
early autumn plumage of softer and grayer colors, withott white blotches,
which doubtless fits it to live more among the rocks, and less among the
grasses. The colors of ptarmigans, in fact, are almost interminably various, from
month to month. It seems almost as if they underwent a perpetual moult. The
grass-pattern plumage of the nesting season, however, must be very constant.

* These will be considered later.

Photographed from nature by C, Reid, W:
duced hy courtesy of “Country Life,”

haw. Repro-
London,

Fic. 46. Young Western Meadowlarks in their ground nest. ‘Grass-
: pattern’ birds,
Photographed from life by Cherry and Richard Kearton Photographed from life by Finley & Bohiman.

» Fic, 45. Nesting Scotch Grouse (Ptarmigan).

Fig. 47, Nesting female Eider Duck. Ground-picturing pattern, based on counter-shading.
Photographed from nature. By courtesy of ‘Country Life,’’ London.

Fig. 48. Young Short-eared Owls, in their nest on the ground.
Photographed from life by Cherry and Richard Kearton.

Another kind of Ptarmigan of which we have secured good photographs
from life is the Lagopus scoticus, the so-called “Grouse” of the British Isl-
ands (Figs. 44 and 45). This is preéminently a bird of the heather, and it is
gratifying to see how subtilely and significantly its markings differ from those
of the American species which nest among grasses. It is completely covered
with wonderful heather-pictures, recognizable as such even when the bird is
examined away from its true environment. The more complex forms of the
crowded and delicately branching heather plants, with their twigs and leaves
and blossoms, are copied by various modifications of the bird’s pattern. Rel-
atively to that of the grass-ptarmigans this pattern is characterized by the
multiplicity of its small, light-colored forms, which are also greatly more var-
ied both in shade and color, to simulate the complexer surface-pattern and in-
terior-vistas of the heather plants, with their variously illuminated details.
(Technically, the difference consists chiefly in the wider and wavier marginal
bands, and in a copious speckling of darker brown upon the fuscous ground-
color within these bands.) The bird shown in Fig. 40 was unfavorably ar-
ranged as to obliterative shading, but certain features of its obliterative pat-
tern are shown off to consummate advantage. The pattern of its rump and
back is scarcely recognizably different from that of the heather around its tail
and nearer wing, while the picturing of heather-bells by its breast-pattern is
astonishingly close. The obliterative shading of this species is so extremely
slight that we must infer that it is wont to lie very deeply settled into the heath,
and often more or less overarched by it, so that the preponderance of direct
top-light is reduced to a minimum. The dark area on the actual belly, which
this species shares with several other gallinaceous birds of different genera,
has little or no bearing on the case, as it is invariably out of sight when the
bird is ‘lying close.” (The use of such markings will be discussed in a later
chapter.) The ptarmigans which resort often to bare ground and rock, as
also the arboreal Galline, lack this ‘squatting-patch,’ and light bellies are
essential factors of their concealment. Even some of the rock-haunting
ptarmigans, however, have a somewhat weak obliterative shading, and this is

in keeping with the fact that on mountains there is an unusually great pro-
portion of szde-light.

Still another notable type of pattern worn by birds of grass-lands and the
open plains, is composed of a system of bold transverse bars of black and
brown, or kindred colors. This exists, for instance, on some of the Tinamous
(Tinamide) of South America, and, in a very high state of development, on
the European Great Bustard (Otis tarda). Its effect is much the same as
that of the other grass-patterns, but it seems in most cases to be a cruder and
less highly finished form. The pattern of the Little Bustard (Otis tetrax) is
somewhat of this type, though refined toward elaborate picturing, and is very
beautiful and effective. The female especially is one of the most exquisitely
counter-shaded and picture-patterned of birds.

Vic. 49, Yellow
Wagtail amid
grasses.

Photographed from
life by Cherry and
Richard Kearton.

< ty ass

fw
Send

‘a

~=
bo

—

SN
SAS
Ma A

Fic. 50, Male Bob-white
(Colinus virginianus) on its
nest. Highly-developed pic-
ture-pattern, based on full
obliterative shading.

Photographed from life by
Maunsell S. Crosby. Courtesy of
‘* Bird Lore.”

FG. 51, Male Golden Plover with chick, in grass. Obliterative shading and grass-picturing-pattern, etc. This
bird is also a heather-haunter, [See p. 53, Chap.
Photographed from life by Cherry and Richard Kearton.

Fic. 52. Nesting ‘‘ Upland Plover” (Bartram’s Sane; a ‘grass-pattern’ bird.
Photographed from life by J. E. Seebold

CHAPTER VIII

BACKGROUND-PICTURING ON OBLITERATIVELY-SHADED BIRDS, CONTINUED.
THE VARIOUS PATTERNS OF SCANSORIAL BIRDS

CANSORIAL birds are for the most part tree-trunk climbers. They are

the Woodpeckers (Picide), the Wrynecks (Jyngide), the Nuthatches

(Sitting), the small Northern Creepers (Certhiwd@), the Wood Creepers
(Dendrocolaptide), and a few other forms.

Most of these birds—notably both families of Creepers—spend almost
all their time in a nearly vertical position, clinging to the bark of tree trunks
with claws and tail, or claws alone. The Nuthatches climb head-first down-
ward as well as upward, the others seldom or never do.

In spite of the erect climbing-position in which they spend their lives,
these birds are almost without exception dark on the back and light on the
breast and belly, and many of them have a delicate, complete gradation from
the dark side to the light. The underside may be pure white, as in the case
of many woodpeckers, or brown, barely lighter than that of the back, as in
some of the Dendrocolaptide. But in the whole catalogue of species we
know of none which is not thus counter-shaded, more or less pronouncedly.
But how, then, the reader may ask, does this regulation counter shading con-
‘ form with these birds’ vertical habit of life? ‘The answer is plain. The solid,
leaf-crowned trunks up which they climb cut off the light from their breasts,
and almost all that reaches them strikes laterally or diagonally on their backs.
It is the same scheme over again, but carried out on a vertical instead of a
horizontal plane.

The patterns of these climbing birds are extremely various, ranging from
none at all, as in some of the Wood Creepers, etc., to exquisitely elaborate

bark- and vista-pictures much like those worn by goatsuckers, as in the Wry-
necks.

The unmarked Wood Creepers—whose counter shading also, in some
cases, is very slight—frequent brown stumps and trunks, in very heavily
shaded forests. Other members of the same family, with closely similar
habits, have streaks and a more pronounced counter shading.

Bark picturing plays a very large part in the disguises of several classes
of animals, probably reaching its consummation among moths and _ butter-
flies, as we shall see later on. Cruder * forms of it among birds are represented
by the streakings and mottlings of the Creepers (Certhiide and Dendrocolap-
tide), by the close transverse barrings of the backs of certain Woodpeckers,
and the bold spottings and stripings of other members of that family. All
these devices, especially the barrings and stripings, are, at a little distance,
effective bark-pictures. The pattern of the small Northern Creepers (Cer-
thia) is perhaps too highly developed to be rightly classed among these others,
and should be treated rather as a connecting link between them and the ex-
quisite picture-pattern of the Common Wryneck (Jynx torquilla). This last
is one of the most wonderfully equipped and beautiful among obliteratively-
colored birds, and is evidently one which, like the goatsuckers, often stays
stock-still in time of danger, allowing its enemy to make an exceedingly near
approach before it moves. Its buff-colored breast and rufous primaries bear
the same form of transverse dusky barring as is worn by so many of the larger
forest birds, while its back is mottled and lined and peppered with several
tones of gray and dusky, in minute picturing of bark seen at close range. In
back view the bird would usually be seen against the very tree to which it is
clinging, in side view usually against branches and trunks, and more distant
forest vistas. And behold! its markings are developed correspondingly.

* Whenever we call a coloration cruder, or less developed, without trying to state the function
of this so-called crudeness, it must be understood that such a function surely exists. It is, evidently,
only the need of this coloration to represent different backgrounds, that can limit its development
toward any particular one.—A. H. T.

On its sides (breast, cheeks, flanks, wing-coverts, etc.) are the delicate twig-
and vista-pictures, and on its back the near-bark marblings. The beautifully
banded tail serves well in either view. Indeed, the Wryneck’s oblitera-
tive coloration involves the same principles and sorts of background pictur-
ing as does that of the Ruffed Grouse and other forest birds described in
Chapter VI.

We have now glanced at most of the main types of coloration among tree-
trunk-climbing birds. In a later chapter I shall recur briefly to the subject
of the bolder markings of woodpeckers and nuthatches.

CHAPTER Ix

BACKGROUND-PICTURING ON OBLITERATIVELY-SHADED BIRDS, CONTINUED.
BEACH-SAND- AND PEBBLE-PATTERNS OF THE SHORE BIRDS (Limicole).
GENERALIZATIONS AND COMPARISONS

BLITERATIVE shading, pure and simple, is the rule among the Shore
Birds (Limicole). ‘There are a few somewhat anomalous cases—
e. g., the summer costumes of the Golden and Black-bellied Plovers, and the
Dusky Redshank (Totanus fuliginosus), which we will consider later on;
but for the most part the birds of this order show great simplicity and uniform-
ity in their obliterative coloration. The markings of many of the species
which inhabit pebbly shores and wave-marked, sandy beaches are much like
those of the grass-pattern birds described in Chapter VII, but even simpler.
Littoral flats, whether of sand or shingle, are for the most part characterized
by great monotony and blankness, being governed by few and simple laws,
and almost wholly wanting the complex element of vegetable life, with which
we have had mainly to deal in the foregoing chapters. Since the birds that
inhabit these beaches are almost all great wanderers, making long semi-
annual migrations, one would expect to find their patterns not only simple
but highly generalized, and varying little among the species. A comparison
of the more strictly littoral among the smaller shore birds will show that this is
actually the case. There are, indeed, two quite distinct types among them,
but almost all the species belong to one or the other of these two. The one
includes those which are largely destitute of picture-pattern—e. g., the smaller
plovers (4¢gialitis), the other those which are well provided with such pat-
terns, of a regular and simple kind—e. g., many of the sandpipers (Tringa,
etc.). The patterns of sand and shingle and tidal mud flat are apt to be so
slight that a bird can be well concealed on such ground by counter shading

and color alone, as in the case of the plovers; but Nature has given many of
her beach-birds a picturing of the faint patterns. Wave-lines left at low
tide on bright sandy beaches, narrowed in perspective, the lines of small
lapping rollers over shallows, strips of stranded driftweed, shells, heaped or
scattered, straggling blades of beach grass—these, varied by the even speck-
ling of broad pebble-beds, are the chief features of the ground-scene on blank
shores where sandpipers and plovers troop and feed. So do we find the
bird’s pattern, wherever it occurs, delicate and linear and wavy, with few in-
tricacies, and a persistent tendency toward lengthwise striping and crescentic
spots. The effect may be produced by light markings on dark, by dark
on light, or by both; but the patterns are all much alike in general character.
Marginal bands play the chief part in all these simpler picture-patterns, and
this is even truer of the beach than of the grass type. ‘These two phases of pat-
tern are well connected by intermediate forms, worn by some of the Limicole
that live more or less largely in the fields or moorlands. Such are the Cur-
lews (Numenius), already mentioned among grass-pattern birds, the Thick-
knees (Gidicnemide), and the North American Bartram’s Sandpiper (Bar-
tramia longicauda), which has, indeed, one of the most highly specialized of
‘srass-patterns.’ (See Fig. 52 and Chapter VII.)

Again, among the true plovers we find an outcropping of the heather pat-
tern, in conformity with the heath- and tundra-haunting habits of the birds
that wear it. Such are the several races of the Golden Plover (Charadrius),
which breeds in the far north of both continents, and, to some extent, its rel-
ative the Black-bellied Plover (Squatarola), of like distribution.

Good examples of the pure beach type are the winter costumes of the
Knot (Tringa canutus), the Sanderling (Calidris arenaria), the Semipalmated
Sandpiper (Ereunetes), and the Stints (Tringa minuta, T. temminckii, etc.).
Most of the birds of this family wear a more grass-like pattern in summer
than in winter, a fact which is in perfect keeping with their habits, for during
the nesting season they tend to forsake the beaches and to live among
the weeds and grasses. Some, like the Pectoral Sandpiper (Tringa

maculata), stick to grassy swamps throughout the year, and their pattern
tells the tale.

The true snipes (Gallinago), already treated of in another division because
of the rich intricacy of their markings, have a pronounced element of grass-
pattern, and both in markings and in habits form a connecting link between
the grass birds and the woodland bog birds, typified by the American Wood-
cock (Philohela minor). In like manner the sand- and pebble-type of pattern
is modified toward rock-surface picturing,—as in the winter plumage of the
Purple Sandpiper (Tringa maritima), one of the most highly ‘obliterated’
of birds, and a sandpiper peculiar in its restriction (at least in winter) to rock-
baund ocean shores. In the same way the pattern of the terrestrial goat-
suckers, described in Chapter V, is modified toward rock-picturing in the
plumage of that rock-haunting member of the family, the Nighthawk (Chor-
deiles).

From all this it appears that the types and forms of picture-pattern worn
by birds, though easily separable into classes when grouped about the several
conspicuously pure examples, are yet in the whole range of species closely
blended and intermingled, more or less irrespective of the structural affinities
of the birds which wear them, but nearly always in obvious conformity with
their specific habits. It would seem, indeed, as if Nature in its entirety
should represent one great, blended scale, shaded throughout insensibly like
the colors in the spectrum, and as if the breaks and interruptions which form
the bases of zodlogical classification and separate grouping were in a sense
imperfections. In the world of birds, for instance, though the breaks and
anomalies are numerous, there are yet many evidences of the past existence of
a smooth gradation connecting types now sundered.* On the other hand, it
is also true that gaps in the fundamental affinities of birds are often super-
ficially bridged over by similar habits, probably of more recent acquirement,
and these are usually accompanied by corresponding outward resemblances,

* See Robert Ridgeway, in the preface to his ‘‘Birds of North America,” whence much of this
thought is taken.

particularly those of plumage. Thus we discover, even in the study of the
disguising-coloration of the birds of to-day, a wonderful intermingling and
gradation between the types, which makes it hard to consider them separately.
But division and classification are essential to analysis, and by taking a prom-
inent type-center as the theme of a chapter, we can better examine both its
differences and its affinities. Those we have already glanced at are perhaps
the most representative and notable of the many types of picture-pattern worn
by obliteratively-shaded land and beach birds. It remains for us to consider
the markings of rails and other swamp birds, of obliteratively-shaded ducks,
etc., and also the several obliterative uses more or less independent of counter
shading which are served by spots and patterns in birds’ costumes.

CHAPTER X

BACKGROUND-PICTURING ON OBLITERATIVELY SHADED BIRDS, CONTINUED.
REED PATTERNS AND OTHER MARKINGS OF BITTERNS. THE COLORATION
OF HERONS IN GENERAL

NE more pronounced. modification of the ‘dead-grass’ type of picture-
pattern must be considered. This is the picturing in a near view of
straight, erect reeds, which exists on the necks and heads of several herons,
notably the American Bittern (Botaurus lentiginosus), which shall serve as our
example. Many herons are wont to stand motionless, with neck and head
extended and erect, and in the bitterns this habit reaches its climax. The
American Bittern will stand for an hour at a time ina swampy meadow, with
scarcely a movement of its erected, straight and stick-like neck and head,
terminating in the long, sharp bill, which points directly upward. When, as
is pretty frequently the case, the neck and head in this position project above
the reeds or grasses, they look, in certain lights, and from a sufficient distance,
like a pointed stick or stub. This fact has been commented on by many
writers, all of whom, it seems, have thought it a sufficient explanation of the
Bittern’s curious trick. Though we admit that the stick-aspect is sometimes
most pronounced, and must therefore have a bearing on the significance of
the habit, we are convinced that this has another function of far greater im-
portance, namely, the display in correct position, and with the clearness
gained by depressed feathers, of the reed-stripes on the upper neck, which
extend sharp and unbroken over the head, and are even continued on the
bill. The following extract from my journal, recording my first recognition
of the high obliterative efficacy of these stripes, contains some details which
make it worth quoting: ‘But if this [stick-mimicry] were the explanation,
what would be the function of the finely developed, sharply contrasted stripes
56

of light and dark, running lengthwise of the head and neck, and best shown
when the bird is standing erect in the attitude alluded to, with feathers closely
depressed? It is plain that these markings cannot help the ‘stick’ aspect,
but must rather injure it, inasmuch as a single stick or stem would be of uni-
form coloration, or at most mottled, rather than marked with sharp and strong
longitudinal stripes. The true explanation flashed into my mind to-day as
I was watching a standing Bittern at a distance of about ten feet. The light
stripes on the bill were repeated and continued by the light stripes on the
sides of the head and neck, and together they imitated very closely the look of
separate, bright reed-stems; while the dark stripes pictured reeds in shadow,
or the shadowed interstices between the stems. The truth of this explanation
must be apparent to any one with an eye for such things, who watches at
close range a Bittern standing motionless among reeds.” To be sure, Bit-
terns’ heads and necks are often seen projecting stick-like over the tops of
meadow-grasses and half-grown reeds, but who knows how many times Bit-
terns’ heads in this same attitude among the reeds escape all notice, by virtue
of their beautiful rush-pattern? It may very well be that the projecting-stick
aspect is, relatively at least, exceptional and unimportant. My own obser-
vations of Bitterns in their haunts all tend toward such a conclusion.

Reed-like patterns occur also, though in less marked development, on the
necks of some of the true herons, as for instance the Purple Heron (Ardea
purpurea) of southern Europe. The beautiful European Bittern (Botaurus
stellaris) has kindred markings with a strong admixture of richly brindled
grass-pattern—a pattern at once bold and subtile, whose obliterative effect
in the bird’s normal environment must be consummate. So also with the
South American Botaurus pinnatus. The Least Bitterns (Ardetta), of Eu-
rope and America, have also delicately reed-marked heads and necks. There
are doubtless many other examples which might be cited, but these are all
that occur to me.

A modification of the type of grass-pattern described at the end of Chap-
ter VII occurs on the South American Tiger Herons (Tigrisoma), with their

minute transverse barrings or grizzlings of olive and black. Like the bit-
terns, they are inhabitants of reed and grass swamps. All these birds have
obliteratively-shaded bodies, and—in the slight degree consistent with the
characteristic nearly erect position of these parts—obliteratively-shaded necks
and heads.

The coloration of herons in. general is exceptionally various, including as
it does such extremes as the richly mottled brown of bitterns and the immacu-
late snow-white of egrets and some others,—the supposed ‘‘conspicuous”’
species. (In a later chapter we shall show that these egrets too, and all such
birds, are obliteratively colored.) Herons walk and rest, very commonly,
almost erect, and their obliterative shading is often not very pronounced,
though present, and evenly developed, in the majority of species. The colors
of shallow and shaded water—subdued blues and greens and purples, some-
times enriched and subtilized by iridescence,* predominate in their plumage,
and they usually have bright reed- and water-colors on their naked legs and
bills.| Their markings are various, sometimes pronounced and clear, some-
times obscure, or even lacking altogether, but almost always perfectly and
obviously consistent with the water-picturing suggested by their general color-
tones. It is significant, too, that in spite of the much diversity in herons’
colors, there are no brown and elaborately-patterned species except some of
those that live in grassy marshes and dense reed-swamps, where they skulk
almost like rails—the first subjects of our next chapter.

* See p. 92, Chapter XVI.
{ See Chapter XV.

Fic. 53,.- «tmerican Bittern on its nest, ‘obliterated’ by picturc- Fie. 54, Nesting Virginia Rail, ‘ubliterated’ by counter-shading
pattern based on counter-shading. (The ‘reed-stripes’ mentioned in and background-picturing pattern.
the text are here not in full operation.’ Photographed from life by E. |. Tabor,
Photographed from life by E. G. Tabor.

Fie. 55. Wilson’s Tern on its nest. (Counter-shading and) ‘ruptive’ pattern.
Photographed from life by Francis H. Herrick. Courtesy also of G. P. Putnam's Sons.

PLATE Il

AORN & CO, BALTIMORE .

EXPLANATION OF PLATE III

MALE WOOD DUCK ON SHALLOW WATER.

Sketch’ by Richard S. Meryman

MALE Woon DUCK IN A FOREST POOL.

Painted by Abbott’H. Thayer, assisted by Richard 5. Merman

_ Qhe bird wag painted from a stuffed specimen, and the |
background copied, color-note for color-note, from the bird

" himself. Cf. the backgrounds of the: Rattlesnake, Figure
123; the Bird-of-Paradise, Plate VI; and the Flamingoes.

CHAPTER XI

BACKGROUND-PICTURING ON OBLITERATIVELY SHADED BIRDS, CONTINUED.
WATER MARKINGS AND COLORS

HE duskiness of obliterative shading on such birds as rails, gallinules

and coots, is in keeping with their habit of skulking under deep marshy

cover, closely shaded from the direct top light, and often, momentarily, lighted
more from the side than from above. A true obliterative shading exists, how-
ever, on almost all the species. Two or three main types of coloration prevail
among them, but there is little variation beyond these types, and only such
as is consistent with ‘obliteration.’ The colors of water, much like those
worn by herons, predominate among the more aquatic species, the coots and
gallinules. Olive, green, blue, purple, slate-gray, dusky—these are charac-
teristic gallinule colors, and likewise the colors of water. A few of the birds
that wear them are scantily or not at all counter-shaded. The Purple Galli-
nule (Jonornis martinica) for instance, with its bright but softly-blended water
tones, is as dark beneath as above, though there is a counter shading from
the middle of its back to the lower edge of its folded wing. It lives for the
most part over deeply and diversely shaded pools, and amidst the big, glisten-
ing leaves of water plants, and its peculiar coloration does certainly achieve
adequate ‘obliteration.’ (This will be explained more fully in a later chap-
ter.) It is noteworthy, however, that in almost all cases where the adult
plumage of one of these swamp-haunting species lacks obliterative shading,
that of the young possesses it in full. This is true not only of the Purple Gal-
linule, but in a remarkable degree of some of the jacanas, as the common
Jacana jacana of South America. These birds live in tame and noisy flocks

on shallow lakes, lagoons, and miry marshes, and, unlike rails and gallinules,
they do not skulk and stick to cover, but stay almost always in the open reaches,
where they are exposed to the view of predatory birds and beasts. The adults
are black underneath and rich red-brown above, with pea-green wings. As
birds go, they are apt to be conspicuous, although not always easily discerni-
ble amidst the multitudinous sharp lights and shadows of the labyrinths of
lily pads over which they often walk. Watching a flock of jacanas feeding un-
der the noonday sun, one sees from a little distance mainly the black-breasted
adults—of the more daintily-colored, white-breasted young there seem to be only
two or three in the whole flock of a score or more. But when the horizontal
sun-rays of late afternoon or early morning stream across the marsh, behold a
revelation! The young, concealed till now by their counter shading, show up
in quantities, outnumbering the adults almost two to one. This is a most
beautiful and convincing exhibition of the power of obliterative shading, and
one which must leave a lasting impression on the mind of every observant person
who sees it. But it suggests also an interesting question—so interesting that,
though it leads us into the tabooed region of hypothesis, we must be permitted
to discuss it briefly. Why are the adult jacanas deprived of the counter shad-
ing which served their youth so well? Adult gallinules also, it is true, lack
counter shading, but they are always alert to skip into deep cover at a moment’s
notice, whereas the jacanas, as I have said, live in flocks, conspicuously ex-
posed, in the open tracts of lagoons and marshes, and rarely or never take to
cover unless wounded. Is it not highly probable that the strong spurs on
their wings have something to do with all this? May it not be that the
young, weak-spurred and inexperienced, need concealment in situations where
the adults, with their hard, sharp thorns, are well able to protect them-
selves? * Undoubtedly, the dark-hued parents must often serve to distract
the attention of predatory creatures from their obliteratively-colored but
defenseless young. Certain it is that these spurs are not, like those of cocks

* There must, of course, be situations where the adults are as obliteratively colored as the young. —
A. H. T.

and pheasants, for battles among the birds themselves, for they are worn
equally by the small males and the much larger females. Evidently, then,
they are for defense against outside enemies, such as alligators, iguanas, tor-
toises, and predatory birds and mammals. That they are very effective
weapons seems to be attested by the birds’ abundance, noisiness, and tame
and nonchalant manner.

The colors of rails differ from those of gallinules and coots (and differ
even among the several species), exactly as do their habits. They are more
terrestrial, and their general color-scheme accordingly is browner. The
backs of many species bear a subdued and dusky striate pattern of the ‘grass’
type—richer and brighter on the more terrestrial kinds, and vice versa. (See
Fig. 52.) Some are slate-gray underneath, others pale rufous, or grayish
white; but almost all have a complete counter shading, with a light culmi-
nation on the vent and belly. Some, like the Yellow Rail (Porzana novebor-
acensis), have a background-picturing pattern of delicate, grasslike, pale-
brown barrings. But it is the patterns for which the birds of this family are
peculiar that we have here to consider. These are the characteristic bar-
rings on the flank feathers (in Rallus) and the system of pure-white specklings
and slender stripings on the dark-colored upper sides (in Porzana)—mark-
ings which, although not, indeed, strictly limited to the rails, yet reach an
unusually high degree of development and significance among them. Water
pictures of some kind they plainly are; and it is not difficult to go further and
perceive what details and aspects of reed-swamp surfaces they most resemble.
The white punctations picture broken glints of sky-shine on the dusky water,
seen beyond and through the dim vegetation-pattern, rendered by the darker
markings of the birds’ backs. The barred flank-pattern pictures glimmering
water intersected by bold shadows from the reeds—or by intervening shaded
reeds themselves. That crane-like relative of the rails, the Courlan (Ara-
mus), the ground-color of whose costume is the deep, dull brown of heavily
shaded, muddy water, has likewise a water-glint pattern of pure-white spots
on its head and neck. This I have seen performing admirably its ‘obliter-

ative’ function, on a wounded bird in hiding. The white specklings of some
of the Wood Sandpipers (Totanus) and various other water-haunting birds
(e. g., the loons, Gavia) belong more or less strictly to this same class of
‘water-glint’ pictures.

So, too, the rails’ barred flank-pattern has affinities with the markings of
other water birds, such as certain ducks. On them, however, it is developed
into ripple-picturing. The beautifully contrasted black-and-white bars on
the flanks of the Wood Duck (Aix sponsa) are ripple pictures, and as potent,
in their place, as the most elaborate markings of land birds—while they are
even more remarkable in that they depict motion. These markings of the Wood
Duck cross the flank feathers transversely, yet when the feathers are laid
in their natural upcurled position, overlapping the wing, their pattern forms
one brilliantly accentuated horizontal stripe. ‘Thus, though made by flank
feathers, this marking is merely another form of the longitudinally striate
scapular- or wing-pattern worn by so many other ducks, and serves ex-
actly the same purpose. More than two thirds of the American and
European ducks have one form or another of this marking, and on many of
them it is most pronounced. It corresponds to the ‘secant’ stripe of certain
land birds, but is often more elaborate (consisting sometimes of several tiers
of stripes), and has an even more definite ‘obliterative’ use. It may be seen
in its perfection on the Wood Duck, already mentioned, on the Pintail (Dafila
acuta), the Green-winged Teals (Vettion), the Garganey (Querquedula circia),
the Widgeons (Mareca), the Golden-eyes (Clangula clangula, etc.), the Long-
tailed Duck or Old Squaw (Harelda hyemalis), the Steller’s Eider (Eniconetta
stellert), the Hooded Merganser (Lophodytes cucullatus), and the Red-breasted
Merganser (Merganser serrator). Its position varies from the flank feathers,
as in Aix, to the secondary wing feathers, as in Merganser, the tertiaries, as
in Mareca, and the scapulars, the feathers of the sides of the back, as in Dafila,
Nettion, Harelda—in fact, the great majority of species. Its character and
effect, however, are nearly the same in these several positions. A swimming
duck leaves a spreading, wedge-shaped trail of curling ripples, very noticeable

in quiet water, while shorter ripple-lines also roll out in front of the bird’s
breast. Seen in profile against the water, the duck’s body hides a portion of
the perturbed and wavy surface extending from its further side, and tends to
‘relieve’ noticeably against it. But this ‘relieving’ Nature combats with the
bright ‘secant’ stripes, which, by their beautiful likeness to rolling wavelets,
with shine and shadow, go far toward ‘merging’ the duck’s otherwise well
‘obliterated’ body into the troubled water beyond it. The peculiar ripples,
real and pictured, may still suggest a swimming bird, but just where the bird
really is—where alone the eye is led to expect it—there seems to be nothing.
but water,—for the wave-lines extend across its dim body. This is a very
important factor of disguise among ducks, particularly those that inhabit
quiet inland water. Among deep-sea ducks it is less common. But the
same system, sometimes elaborated, and including sharp transverse markings,
occurs on a few of the oceanic species.

Another peculiar form of pattern, common to even more kinds of duck,
is a fine, black or gray vermiculation of the back or sides, as on Teals, Scaups,
Canvasbacks, Wood Ducks, and many others. Indeed, this pattern is al-
most universal among ducks, and there are comparatively few (these mostly
deep-sea kinds) that lack all trace of it. It serves as a generalized picturing
of shimmering water, fretted with broken shore-reflections, or ruffled into tiny
ripples by light breezes. Considering its prevalence among highly ‘obliter-
ated’ water birds, one can hardly doubt that such is its main function. On
some species which frequent shallow inland waters, like the Wood Duck and
the Hooded Merganser, the dusky vermiculation is exceedingly close and
delicate, over a ground-color of golden brown. In these cases it seems to
picture the sandy bottom seen through shallow water at the stream’s or
pond’s edge. As a rule, the vermiculated pattern occurs on the sides, and
its minuteness therefore fits it to match its wearer’s more or less distant
watery background, with its ripples and reflections dwarfed and refined
by perspective. The much coarser wavy markings of some geese, though
they serve also the purpose of ground-. and grass-picturing, in conformity

with the birds’ half-terrestrial habits, have yet much in common with ducks’
grizzled water-patterns; and the two types are connected by intermediate
forms, e. g., the breast-pattern of the Ruddy Duck (Erismatura jamaicensis).

Ducks have still another very characteristic obliterative marking, the
bright-colored ‘‘speculum”—a broad band, often of metallic green, blue, and
purple, crossing the middles of the secondary wing feathers. This marking
can but poorly serve the purpose (commonly supposed to be the main function
of all such marks) of display in flight, for the color is confined to the tops
of the outer webs of the wing feathers, and so only makes a continuous band
when the wing is folded. Its obliterative use, on the other hand, is most
pronounced. It gives the effect of a ‘window’ through the body of the bird
to the water or vegetation beyond.*+ This speculum is almost always of some
characteristic water tint—blue, green, or gray. Often it is highly iridescent,
which makes it additionally effective (as will be explained at length in a later
chapter). On some species, such as the Scaups (Aythya marila, etc.), it is
white. But even pure white serves the same ‘obliterative’ purpose, picturing
a sky-reflection on the background-water.

All these factors in the disguising costumes of ducks are usually parts of
an ‘obliterative’ scheme based on full obliterative shading. Very few ducks
lack this counter shading, and most of them have it in full development,
particularly the females, and the males in post-nuptial summer plumage.
The singular change to a dull-colored summer dress, like that of the females,
which most male ducks yearly undergo, is coincident with their loss, and lack,
for many weeks, of all flight-feathers. Discussing this phenomenon, an
eminent English ornithologist remarks:{ ‘‘Most of these birds (Anatide)

* Much the same purpose is served by the beautiful metallic spots or patches of water-color
(deep blue, green, and violet) on other parts of the body, worn by many sea ducks, notably Steller’s
Eider. This bird has indeed a supremely beautiful pattern of ice and water pictures.

+ Little used while the duck is swimming, but greatly when he walks about on the adjacent shore,
in far greater danger from his enemies. These speculums prove, also, to have a wonderful power to
obliterate their wearers against the sky, to the eyes of creeping enemies that flush them.—A. H. T.

t See the ‘‘Encyclopedia Britannica,” vol. iii, p. 776 (of the R. S. Peale Reprint).

shed their quill-feathers all at once, and become absolutely incapable of
flight for a season, during which they generally seek the shelter of thick aquatic
herbage, and it is further to be particularly remarked that the males of two
sections of the family (Anatine and Fuliguline) at the same time lose the
brilliantly-colored plumage which commonly distinguishes them, and ‘go into
eclipse,’ as Waterton happily said, putting on for several weeks a dingy
garb much resembling that of the other sex, to resume their gay attire only
when, their new quills being grown, it can be safely flaunted in the open air.”
Here are the facts, but without the true conclusion which’ should be drawn
from ttem—the conclusion which is unavoidable in the light of a wider
knowledge of protective coloration. This is, that the male duck’s assumption
of dull plumage is an adaptation to his new environment, rather than to his
altered bodily condition. We skulks among the reeds because he is flightless,
and he assumes a mottled grass- and reed-like pattern to fit him to this new
environment; but the mottled pattern is no more protective, i. e., ‘obliterative,’
than the pied waéer-pattern of his full plumage, worn when he forsakes the
shelter of the shore. Male Eiders (Somateria) keep out at sea while their
brown, mottled females (see Fig. 47) hatch the eggs (sometimes a long way
from the water) and tend the young, and though the males (as well as the
females) are flightless for a while, they retain their full plumage almost un-
altered. This full plumage has no obliterative shade-gradation, but con-
sists of a bold ‘ruptive’ pattern of ice- and water-colors—as will be further
explained in a later chapter. A few male sea-ducks, such as the more or
less wholly black Scoters (Oidemia), are conspicuous at sea, though well
equipped for inconspicuousness against dark cliffs. Their females, which
have to brood the eggs on shore, are more or less adequately ‘obliterated’
by counter shading, color, and markings. There are, however, some species
of swimming birds in which even the females are quite without counter
shading. Such are swans,* for instance, and cormorants—though cormo-
rants are otherwise equipped for concealment on shore by rock-like
* See p. 154, Chapter XXII.
65

markings, and by iridescence, which must often admirably mask them under
water also.

The foregoing sketch of ducks’ disguising coloration touches on most
of the main general facts. But the reader must now be subjected to a de-
tailed description of the obliterative equipment of one particular species, the
Wood Duck, the male of which is almost unsurpassed among birds in the
combined boldness and intense subtlety of its disguising coloration. (See
Plates IIJ and IV.) The general scheme of this beautiful bird’s ‘disguise-
ment’ includes a full and potent obliterative shading, from blue-black on
the back and tail to pure white on the entire underside, shading through
sand-color on the flanks and through chestnut, mixed with white, on the
breast. The throat also is white, ending abruptly against deep velvet bronze
and purple on the cheeks. Founded on this, underlying obliterative shading,
which cancels the bird’s visible solidity, and prepares him for ‘background
matching,’ there is a bright and beautiful system of water-pictures, of many
kinds, bolder and more vivid than those of any other bird we know (with the
possible exception of Steller’s Eider). For the most part, these pictures are
of shore- and sky-reflections, subtilely and richly intermingled, and comprising
a great variety of effects. The colors are mainly deep and soft, though rich,
and liquidly alive with sober iridescence. Their range (excluding the sandy
flanks) is from chestnut red glossed over with purple, through all degrees of
blue to golden green;—perfect woodland water colors, all of them. Olive-
ash color occurs on the lesser wing-coverts and primary quills, and this, the
tint of lusterless still water near the shore, between reflections, is a connecting
link between the brighter water-pictures and the sand-colored sides. The
scapulars, which meet over the back, are somber blackish, with a glimmering
of blue; water deeply shaded, showing a dark bottom, or reflecting something
dusky. The “speculum” and some of the greater wing-coverts, together
forming a patch which intervenes between the back and flanks, and, longi-
tudinally, between the two areas of ashy olive, are bright and lustrous blue,
ranging from almost purple to deep robin’s-egg, and including also, on a single

feather of the speculum, a blended patch of copper red, sometimes combined
with greenish bronze and purple. All these feathers are iridescent, but their
changeableness is mainly from dusky to bright, rather than from one bright
tint to another. They render beautifully a portion of the surface of the dim
translucent water where there is a somewhat vague reflection of the sky or of
plants above. Forward, this patch is blended softly into the ashen olive of
‘the wing-coverts; while the speculum is bordered outwardly with a band of
white—like a sharp streak of the clearest sky-reflection on the elsewhere dim,
semi-transparent water. So, in lesser degree, with the grayish-white longi-
tudinal stripe formed by the outer veins of the folded primaries, above sharply
bordered with dark blue (the outer veins and a narrow stripe next the shaft
on the inner veins of the primaries), and forward blended smoothly into the
ashen-olive patch at the bases of the primaries. This combination of softly
blended with clean-cut, sharp-edged markings is what gives the water-picturing
its peculiar magic, for it represents the two main characteristic elements in
the aspect of quiet water, namely, vistas through the surface into the liquid
depths, and reflections, on the surjace, of things above. As in the duck’s
costume, so in the water which it pictures, these two elements are now sharply
differentiated, and now intimately blended.

Most potent of all, perhaps, are the pictures of reflection on the Wood
Duck’s richly crested, green and purple head, with its clean-cut stripes and
bars of snowy white. These white marks picture bright and sharp reflections
of the sky (their sharpness of outline caused perhaps by straggling wavelets
which ‘cut’ and border them) lying on the dark, translucent water, tinted
by vague reflections from the shore. Or, again, the white and dark marks, all
together, suggest a definite, fixed reflection-picture of a fringe of bushes along
the shore, with the bright sky beyond cutting in among their crowns, and show-
ing here and there between them, lower down. The white on the head and
neck and cheeks shows duly bright, while that on the throat, from which the
higher spots are offshoots, is, in the bird’s normal life-postures, dull with
shadow, and belongs mainly to the obliterative shading. In the resultant

water-picture it renders a duller sky reflection, mixed perhaps with under-
water effect.

The deep chestnut breast is blended above into dusky olive, on the fore-
back and neck, while below it fades away into the immaculate white belly,
the transition being effected by a series of triangular white flecks, extending
downward in crescendo progression from the upper breast. (See, in con-
nection with this and other points in my description, Plates III and IV.) This
rich and lustrous chestnut, fleckless in its anterior and upper third, and glossed
with purple and weak green, is an admirable picture of translucent, shaded
water near the shore, either reflecting faintly the muddy bank and brown-
stemmed bushes, or dimly revealing its own dusky, earth-colored bottom.
Bounding the back edge of this chestnut, and separating it from the wing
and side, is a bold ‘secant’ band of black and white (like that worn by certain
teals, but stronger), vertically extended, but slightly crescentic, and pointing
forward. Sharply ‘secant’—seeming fairly to cut the bird in halves—this
marking is also intermediate in character between the reflection-picturing
patterns of the head and the ripple-pictures on the flanks. For it depicts
with almost equal fidelity at least two types of detail—a narrow sky vista
reflected side by side with a dark stem or tree trunk, and a sky reflection
glancing from the side of a sharp, single ripple. At least two evident purposes
are likewise served by the beautifully graduated white triangles on the chest-
nut breast, downward growing larger and larger until they completely veil
the brown and blend it into the white of the belly. First, they are agents in
the obliterative shading, and second, they admirably picture small glints of
bright reflection on the faintly tremulous surface of quiet, shaded water. In
this function they are the same as the punctate shine-pictures on the backs of
rails, wood sandpipers, loons, etc., mentioned earlier in this chapter.

Chestnut like that of the breast, but more strongly glossed with purple,
forms a broad patch on either side of the Wood Duck’s rump, back of the
ripple-picturing flank feathers. It is unflecked, and blends into the dusky
and velvety-blue-green tail, just as the breast’s chestnut blends into the olive

back. Downward, this rump-mark blends into dusky-olive under-tail-coverts.
Tail and rump together picture a patch of dark water, with blended, weak
reflections, relieved by a streak or two of reflected shore-color in clearer defini-
tion. These streaks, which are shining rufous brown, are formed by the
central barbs of two or three of the loose-webbed, lengthened upper-tail-coverts ;
they relieve against dusky green.

The ripple-, sand-, and water-shimmer pictures on the Wood Duck’s flanks
have been described in an earlier part of this chapter, but to complete this
elaborate account we must revert to them, describing them in greater detail.
The whole extent of the sides and flanks, from the crescent breastmark to
the chestnut patches on the sides of the rump, is occupied by a uniform pat-
tern of minute black vermiculations or undulatory lines, closely crowded over
a ground-color of light brownish yellow. Below, this patch fades into the
white of the belly; above, from a point barely in front of its middle backward,
it is bordered by the remarkably bold and vivid ripple-pictures already men-
tioned, formed by broad, alternate bands of snow and jet. These bands are
on the tips of the longest of the grizzled feathers, and, as has been told, they
cross them transversely, yet by the curling upward of these feathers the bands
are made to form oblique or even horizontal streaks. Rising out of and sur-
mounting the grizzled brown—which pictures either tremulous, opaque water,
or, more vividly, a submerged bed of sand—these richly contrasted black
and white streaks and crescents look wonderfully like a crowded company
of fresh-made, hurrying ripples; just such, in fact, as the swimming bird him-
self produces. Thus the ripple-marks he leaves in his wake and those that
roll out from his further side are continued and repeated on his obliteratively-
colored body, and this gives the final touch of perfection to his ‘vanishment.’
In the marvelous completeness of this ‘vanishment,’ this ‘invisibility’ in full
and near view on quiet water, he is possibly unique among swimming birds.
One may scan a Wood-Duck-haunted pool for many minutes, at close range,
and fail to see the ducks that are floating on it; just as one often looks in vain
for the Ruffed Grouse that is perching motionless in the apple tree. Like

the grouse, like the summer ptarmigan and the woodcock, the duck is, as it
‘were, ‘dissolved’ into its vari-patterned background, by perfect obliterative
shading and picture-pattern.

Two details of the male Wood Duck’s costume have yet to be mentioned,
his gaudily-painted bill and his marbled under-wing-coverts. The bill is
marked with bright yellow, red, white, and black, and in connection with the
varied water-scene rendered by the bird’s plumage, it must often pass for a
reflection-picture of bright-colored things like flowers, on the shore—or per-
haps for the actual blossoms of water plants. But it is to be supposed that
the flowerlike aspect of the bill renders its owner a still more direct and simple
service, by separately disguising that implement of offense from the insects
and other small but active creatures which form a part of his diet. A pied,
flowerlike bill would probably, in the long run, succeed better in the capture
of its agile prey than would a dull and normally tinted one, without deceptive
color or markings. Of this the reader is to hear more in a later chapter.

The use of the black-and-white marbling of the under-wing-coverts and
axillars, shared by both sexes, is not surely apparent. But it seems likely that
both the color and the markings of these feathers serve chiefly or wholly for
‘obliteration,’ coming into play when the birds are sitting and walking about
in trees (a habit highly characteristic of the species), with wings frequently
half spread. The ground color of white then becomes effective in neutralizing
the shadow, as in the case of the belly, and the dusky specks and bars constitute
a generalized obliterative pattern tending to ‘merge’ the wing, visually, into
its freckled forest background. This pattern is in fact closely akin to that
of many out-and-out forest birds.

The female Wood Duck is colored much more dimly than her mate. Her
wings alone are almost exactly the same, and fully as bright; otherwise, her
predominant color, aside from the white of her belly, is ashen olive, lustrous
with green and purple on the back, scapulars, and crown, verging toward
brown on the sides and toward ash-gray on the cheeks, and reaching lustrous
olive-green on the upper sides of the tail feathers. Her flanks show no traces

7°

MALE WOOD DUCKS.

Upper one: Sketch by Abbott H. Thayer,
Lower one: Painting by Richard S, Meryman

These paintings show one of the very common situations in
which the boldest contrasts of a male Wood Duck’s coloring come
into play in ‘preventing his showing his silhouette..

. His dark areas, with all their varied colors, here ‘become a
part? of. the. -like-colored dark reflections in the water, and his
white patterns exactly reproduce ‘the bright sky-reflections, go
- that he is so to speak ‘dissolved’ into the scene.—A. H. T.

EXPLANATION OF PLATE IV

PLATE IV

ANGER & CO BALTIMORE,

of the sand and ripple pictures which are such important details in the ves-
ture of her mate, being marked instead with blurred, broad streaks of pale
yellowish gray, on a ground of olive-brown. On the whole, her costume
lacks pronounced water-pictures, seeming to fit her rather for life in secluded
recesses among reeds and bushes, and for perching among gray tree trunks,
which she has frequently to do in the nesting season. When brooding, al-
though most commonly quite hidden in a hollow tree trunk, branch, or stump,
she is at times more or less exposed to outward view; and this fact also must
have a bearing on the significance of her coloration. When she is sitting in
the hollow end of a large broken branch, perhaps even with some of her fore-
parts projecting beyond its rim, her obliterative coloration must often be most
potent. (Audubon has figured a female Wood Duck in such a situation,and
mentions it as not uncommon.) But aside from their probable connection
with her ordeal of brooding, and guarding her ducklings among the reeds and
bushes, her soft markings and colors and perfect counter shading make her
at all times a thoroughly ‘obliterated’ bird—even though she lacks the bright
and elaborate water-pictures of the drake. Both drake and duck are among
the world’s most subtilely beautiful birds, and their obliterative coloration
demands especial study.

The Mandarin Duck (Aix galericulata) of the Orient, nearly akin to the
Wood Duck in all respects, has an equally beautiful and still more remarkable
costume, but one which is less unmixedly of the water-picturing type. In the
drake’s dress there are a few important peculiarities which call for careful
study of him in his home; but the female does not differ essentially from the
female Wood Duck.

CHAPTER XII
BIRDS OF THE OCEAN

JURE white prevails in the costumes of the long-winged birds that habit-

. ually range the open sea, and their patterns are further characterized by
an almost total lack of small markings. In coloration as in environment,
they are the antithesis of the sedentary and seclusive land birds which live
mainly on grassy ground or in the mottled realms of woodland—such as the
ptarmigans, grouse, goatsuckers, etc., described in earlier chapters. The
Shore Birds (Chapter X) are a connecting link between the two extremes.
As their average environment is much more plain and simple than that of the
grouse or ptarmigan, so are their obliterative patterns much less richly and
elaborately wrought. ‘The step is short from these birds of the barren bor-
derland between earth and sea, to the long-winged rangers of the blank and
hoary sea itself. Here are no sharp and fixed small forms at all, but only the
eternal counterplay of two vast and simple fluent elements, atmosphere and
water. ‘True, even in open ocean there are characteristic patterns made by
the moving waves and ripples, and these are reproduced on some of the ma-
rine animals, notably certain surface-swimming fishes. (See Chapter XXIV.)
But the coloration of the long-winged, wide-ranging sea birds copies the prev-
alent blankness of sea and sky and cloud. Though often resting on the sur-
face of the water, they are of course less intimately bound down to it than the
ducks, auks, murres, etc., being in fact eminently aérial rather than natatorial ;
and this is in accordance with their wanting the wave and ripple pictures
worn by many ducks and murres. Chief among these long-winged sea birds
for delicate beauty of ‘oceanic’ coloration are the Larid@, or gulls and terns.

Nearly white all over though most of them are, in the adult plumage, they are
yet obliteratively shaded, having ‘“‘mantles” of darker or lighter bluish gray
on the back and wings—and in the case of many terns, crown-caps of black—
while all the remainder of their costume, with the exception of a few more
or less dark-marked quill feathers, is, in most cases, fleckless white. Black
markings aside (these we shall discuss later), this obliteratively disposed com-
bination of soft, water- and cloud-like pearly gray with bright, shadow-ab-
sorbing white is just such a coloration as insures its wearers, whether flying
or swimming, the greatest average inconspicuousness against the ocean. Often
they show light against dusky water, but just as often they show dark against
water brightly sky-lit; and hence in many intermediate cases they must pass
unseen, matching their ‘background’ as does the ptarmigan or grouse in its
appropriate domain, although so much less intricately. All this concerns the
aspect of the gulls as seen from above, against the ocean. But they have little
to dread from flying enemies, and the more vital service rendered by their col-
oration is doubtless concealment against the sky above, jrom the eyes of aquatic
animals below them. Like the Snowy Owl, the white herons and egrets, and,
in part, the skunks, deer, antelopes, etc., to be described ina later chapter
(Chapter XXII), these ocean-rangers are admirably equipped for incon-
spicuousness, in a great many views, against the sky itself. Thus, even to the
eyes of their aquatic enemies and aquatic prey, they wear the universal com-
plete obliterative coloration. Pure white or largely pure white though they are,
they must often relieve darkly against the sky, as always when seen directly
overhead. In many views, on the other hand, they ‘melt away’ into their skyey
backgrounds, as do the white, masking rump-marks of many ruminants, and
the white back- and head-patterns of many grubbing carnivores (Chapter
XXII), etc. As the normal background of these sea birds is the unbroken sky,
varied only by unbroken, sky-reflecting ocean, so their prevalent coloration is
such as achieves pure and simple sky- and ocean-picturing. On most of the
true gulls (Lavine) the white of the rump, tail, and entire underside extends also
to the head and neck. The head’s consequent lack of counter shading is

re:

evidently more than compensated by the sky-matching power which uniform,
pure white gives to this most vital and most dangerous portion of the gull,
either when he is resting on the water, with head held erect, or—and perhaps
more particularly—when, as he flies or swims, his head is stooped toward,
to, or even beneath, the surface, in search of food.

White or largely white-marked heads are common to a good many other
birds, not counting the habitual swimmers, which get their living from the
water; witness the Bald Eagle, the Osprey, the Great Blue Heron, etc. In
all these cases they perform the same service of ‘obliteration’ agaist the
sky. Some gulls, on the other hand, such as the Black-head (Larus ridi-
bundus), of Europe, and the Laughing Gull (L. aéricilla), of America, have
dusky hoods enveloping the entire head. All or nearly all the kinds thus
marked are inhabitants of bays and lakes and marshes rather than the open
sea. Furthermore, the dark hood is worn only by the adults in the breeding
season, when, amid the blackish mud and dusky shadows of the salt marsh
or inland swamp, they well serve as ‘ruptive’* masks. So do the jetty
crown-caps of nesting terns—except that these belong to obliterative shading
as well as to ‘ruptive’ pattern. (See Fig. 55.) Like the gulls’ hoods, they
are as a rule features of the breeding season only—in the autumn largely
giving place to white, the regulation sky-matching color. But the black
markings on the quill feathers both of gulls and terns are worn throughout
the year, and probably serve both as ‘distractive’ marks + when the birds
are fishing, and as combined ‘distractive’ marks and ‘picture patterns’ when
they are brooding on shore amid shadows and other dark landscape-
details.

For the most part, however, the coloration of these gulls and terns in adult
plumage is suited to the sky and sea rather than to the land, and they are apt
to be conspicuous on their breeding grounds, by virtue of their paleness.
Their downy young, on the contrary, are almost always well ‘obliterated’

* See Chapter XIII, p. 78.
t See Chapter XXII, p. 151.

by counter shading, color, and near-ground markings.* (See the young gulls
in Fig. 75.) Mottled brown, dusky and gray costumes of various degrees of
darkness are worn for two or three years by the young of the larger gulls,
and it is a noteworthy fact that during this period they are more addicted to
living on and about mud-flats, marshes, and muddy lagoons, than are their
white and free-sea-ranging parents.

Among the other groups of long-winged sea birds, there is a good deal of
diversity in coloration, but at the same time a persistent tendency toward
whiteness and the lack of small markings. Sky-matching costumes, indeed,
reach high and simple development among the gannets, tropic birds, alba-
trosses, fulmars, and others.

The smaller jaegers or robber gulls (Stercorarine) have in the usual adult
plumage full obliterative shading, being fuscous brown or slaty gray above,
and white below, sometimes with small markings (dusky flecks) on the breast
and sides; and their young wear a heath- and grass-picturing pattern of brown
and dusky. But the symmetry of these facts is marred by the existence in at
least two of the three or four white-breasted species of a second adult color-
phase, in which the costume consists of sooty brown with a comparatively slight
counter shading. Here, as in the case of the black leopards and jaguars (see
Chapter XXI, p. 133), there may be something to discover in the way of cor-
responding varietal peculiarities of habits. But jaegers are parasitic harriers
of other birds, and prodigiously swift of wing, so that, except during the
nesting time, they doubtless have comparatively small need of disguising-
coloration. Strange as it may seem, however, a good many other aérial sea
birds are colored much like the melanistic jaegers—i. e., almost uniformly
dark brown or black above and below. Such are several of the Tubinares,—
shearwaters, petrels, albatrosses. But almost all these birds, in addition to
being largely nocturnal, nest in dark earth-burrows or rock-fissures, and this
habit has doubtless a significant connection with their queer coloration.
Many other species of the same families, as well as various long-winged sea

* See Chapter XIV, pp. 82 and 83.

birds of other orders, are obliteratively shaded, from pure white to dusky
brown or gray, with or without connecting middle tones. Though often very
inconspicuous against the sea, such dark-backed birds are of course less well
equipped for ‘vanishment’ against either sea or sky than are the beautiful
white and pearl-gray gulls and terns. These have, indeed, the very acme of
oceanic obliterative coloration.

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CHAPTER XIII

BIRDS, ETC. THE INHERENT OBLITERATIVE POWER OF MARKINGS.
‘RUPTIVE’ AND ‘SECANT’ PATTERNS, ETC.

P to this point we have considered markings and patterns almost solely

as adjuncts and dependents of obliterative shading. As far as ground-
haunting species are concerned, this function of markings seems by far the
most important, but they have yet a separate and inherent significance, which
among non-terrestrial species is often the dominant feature of disguise. As
we have seen, perfect uniformity of coloration makes a thing conspicuous,
allowing every part to assume exactly the aspect dictated by its own form,
without exaggeration or omission. Markings, on the other hand, of whatever
sort, tend to obliterate,—to cancel, by their separate and conflicting pattern,
the visibility of the details and boundaries of form. The main solidity, and
its details, are shown by graduated light-and-shade—the outline, the externai
contours, by relieving either light or dark or differently colored against the
background. To all this markings are unfriendly, both on objects actually
monochrome and therefore visually not so, and on objects which present, with
the aid of counter shading, a perfectly monochrome appearance. Rapid
and manifold are the vicissitudes of illumination and relation to background
of a moving bird or butterfly among trees and open spaces. Now it is dark
against a sky vista, or against brightly-lighted foliage, and the next instant,
by some slight change in its position, or in that of the beholder, it shows light
against dark shadow-spaces. (See Figs. 56-57.) Delicate picture-patterns
cannot avail against these grosser ‘visibilities,’ but strong ‘secant’ and
‘ruptive’ patterns can. If the bird’s or butterfly’s costume consists of
sharply contrasted bold patterns of light and dark, in about equal propor-

tions, its contour will be ‘broken up’ against both light and dark—light
failing to show against light, dark against dark. Such is apparently the basal
and predominant use of almost all the bolder patterns in animals’ costumes.
Often such bolder markings play a part in subtler schemes of picture-pattern;
but, on the other hand, they sometimes work independently of obliterative
shading. ‘Secant’ patterns, however, are almost always in its service, even
when they have some share of independent effect. A good example is the
longitudinal light-colored stripe on the scapulars or wing feathers, so very
prevalent among obliteratively colored birds—particularly those with highly
developed picture-patterns. It is found in its perfection on certain sparrows
and many gallinaceous birds. In almost every case it clearly pictures a
horizontal stick or grass-blade, with its shadow under it; but, picture or no
picture, it tends to cut the aspect of the bird in two. This marking'is found
also on certain kinds of wood frog, and on toads. (See Chapter XXIV.)
There are also vertically ‘secant’ markings, e. g., the white or black-and-
white breast-bands of some teals (Nettion), and of the Wood Duck (Azx),
both mentioned in an earlier chapter. ‘Ruptive’ markings, in general, are
bold, massed patterns of contrasting shades and colors, disposed at seeming
haphazard over the animal’s body, but in reality arranged according to the
rigid laws of disguise. Among birds thus marked, some of the best examples
are sea fowl, Eider Ducks, for instance. Male Eiders, with their big, con-
trasting patches of black and white and buff and green—or grayish blue—
are doubtless very inconspicuous in deep ocean water among ice cakes; while
their brown, grass-patterned mates are well fitted for the task of brooding
their eggs on the dry shore. The non-counter-shaded male Harlequin Duck
(Histrionicus histrionicus), likewise, is in aspect cut to pieces by its queer,
black-rimmed white markings, which look like floating bits of ice, or patches
of snow on rocky shores. Many other sea ducks wear kindred markings,
and so do many land birds and even quadrupeds and other animals. The
more crudely-blotched black and white patterns of certain woodpeckers, the
black caps and white cheeks of nuthatches, and the various bold head-markings
78

&
Fie. 56. Two artificial butterflics, one dusky and one light, seen against a dusky tree-

trunk; the light one conspicuous, the dusky one barely distinguishable.

Fig. 57. ‘The same two artificial butterflies seen against alight background, the dusky one con-
spicuous, the light one barely distinguishable.

These two pictures. show that no one color will conceal an animal that must move across the varied.and varying face of nature.

In our pictures of artificial models we have purposely ignored the factor of interposed vegetation, which in nature plays so large
a part in abetting ‘vanishment’ by obliterative costumes. For we are here studying main principles, divested as far as possible of
accessories.

Fig, 59. Chestnut-sided Warbler (Dendroica pensylvanica) (and Catbird). [Cf Fig, 58.]
Photographed from life by F. H. Herrick, Courtesy also of G. P. Putnam’s Sons.

Counter-shading and general-

Fi, 58, Chestout-sided Warblers (Dendroica pensyleanica),
ized obliterative background-picturing patterns.
Photographed from nature by Francis H. Herrick. Courtesy also of G. P Putuam’s Sons.

Fic. 60. Blue Jays
a their nest, amid
foliage. [See p. 116,
Chap. xi j

Fic. 61. Chickadee at
nest hole Light-and-
shadow-picturing general-
ized obliterative pattern,
most potent in snowy win-
ter. Notice how the black
head-markings ‘merge’
with the dark hole beyond.

Photographed from life by
Finley and Bohlman. Courtesy
also of ‘The Condor.”

Fic. 62. Oystereatcher (Haematopus ostralegus) close to its nest on rock ound.
Counter-shading and ‘ruptive’ pattern, ete. a Sea

Photographed from life by Cherry and Richard Kearton. Courtesy also of Cassell & Co.

Fic. 63. Guillemots on rock, showing ‘ruptive’ coloration. Seen against the sky or (brightly sky-lit sea) they ose,’ so to speak, their light parts; seen against the shadowed
rocks they ‘lose’ their dark parts, and thus their bird-like contours are disguised,

Photographed from life. Here reproduced through the kind of Prof. F. A. Lucas.

of North American Wood Warblers (Mniotiltide), are a few of the many ex-
amples among the smaller land birds. (See Figs. 58-61.)

It might be supposed that a marking in such rank violation of the para-
mount ‘obliterative’ principle as a jet-black breast or belly, with lighter
tones above it, could not fail to make a bird exceedingly conspicuous; but this
is by no means true. Such a marking, especially when it ends sharply against
a lighter tone, thence upward counter shaded, tends in aspect to detach itself
from the rest of the bird’s dim body, and to unite with the background as a
hole or other very dark detail, thereby ‘breaking up’ its wearer’s character-
istic form. This is the coloration for instance of the Black-bellied and Golden
Plovers (Charadrius and Squatarola) in summer plumage, and of the adult
male Massena Quail (Cyrtonyx montezume and its subspecies) of Mexico,
etc. In the case of such birds as the male Eider Ducks, however, there is
virtually no counter shading above or below,—the obliterative scheme con-
sisting almost wholly of a series of ‘breakages’ achieved by sharply contrast-
ing patches.

All these bolder schemes of pattern mask their wearer in a distant view
and in many views, whereas the delicate picture-patterns based on perfect ob-
literative shading play their full part only in a near view and against one par-
ticular type of background. In such a case, details of light-and-shade and
minor surface markings count for much. But give the object a greater dis-
tance from the beholder, and manifold vicissitudes of position and illumina-
tion, and it is contour that betrays it—contour, relieving with varying degrees
and kinds of conspicuousness against varying backgrounds. Combating
this principle, Nature has given many of her animals bold and _ brilliant ‘rup-
tive’ patterns, which insure them, in lieu of elaborate and single background-
matching, the highest average of fragmentary background-matching, in many
situations and from many view-points. (See Plates V and VI.)

CHAPTER XIV

SPECIAL FUNCTIONS OF MARKINGS. BIRDS, ETC. PROTECTIVE COLORATION
OF NESTLINGS

EEDING henceforward the axiom established by the foregoing chap-

ters, viz.: All markings and patterns whatsoever are, under ordinary out-

door conditions, unjavorable to the conspicuousness of the thing that wears

them, we will examine further special phases of disguising-pattern in the
costumes of birds and other animals.

A noteworthy type of generalized picture-pattern occurs, the world over,
on the wings and tails of hawks and owls. Most of them have, in some
plumage, conspicuously banded quills, whose pattern shows to best advantage
on the underside. On some: kinds, like the Goshawks (Astur atricapillus
and A. palumbarius) in juvenile plumage, these bars on the quill feathers
form, when the tail and wings are broadly and fully expanded, a large series
of almost complete concentric circles. Potent must be the obliterative effect
of such a pattern, to the victim at whom the hawk is dashing, or above whom
he is momentarily poised, with widespread tail and wings. The reduplicate
circles of alternate light and dark, extending from the hawk’s dim, streaked
body to the very tip of his great flight-feathers, and averaging more sharply
visible than the actual contours of the wings and tail, practically efface those
members, so that for an essential instant he is as it were dissolved and blended
outward, from a central core, into the banded and streaked promiscuous pat-
tern of the twigs and branches behind and all about him. His menacing
body is the inconspicuous center of a maze of forest-colored circles, bewilder-
ing and confounding to the terror-stricken creature on whom he is about to
pounce. (See Figs. 64-66.) The light bands in these patterns of hawks’

Fic. 65. Part of a Goshawk’s wing seen from
below against pine twigs and sky. [Cf. Figs. 64
and 66.]

Fic. 64, Stuffed Goshawk (Astur atricapilius, young) in winter pine woods,
seen from below as the hare or grouse would see him, wonderfully matehin g,
with the help of counter-shading, his barred background of twigs, sky-glints,
etc.

Fic. 66. The same young Gos-
hawk (.Astur atricapillus) laid on its
back on the forest floor and looking
conspicuously bright. . This reveals
the part played by counter-shading
in the ‘twig matching’ shown by
Figs. 64-65,

Fic. 67. Baby Golden Plover’ (Charadrius
Jfulvus). Counter-shading and blotchy ground-
picturing pattern, eye-masking pattern, etc.
Photographed from life by Cherry and Richard
Kearton. Courtesy also of Cassell & Co.

Fic. 68. Ringed Plover (Aegialitis hiaticula). Fye-
masking and ‘obliterative’ shadow-and-bole-picturing
pattern. Wis black marks, as the reader will see, ally
themselves wonderfully with the dark fissures in his

background.

Photographed from life by Cherry and Richard Kearton.
Courtesy also of Cassell & Co.

’

Fie. 69. Lapwing
(Vanellus capella) on 1ts
nest, Obliterative shad-
ing, eye-masking and
shadow-picturing oblit-
erative patterns.

Photographed from life by
Cherry and Richard Kear-
ton. Courtesy also of Cas-
sell & Co.

wings and tails are almost always very translucent, and contrast brightly with
the opaque dusky bands, even when the wing or tail is seen from below, and
deeply shadowed. As the pictures show, the dark marks are just of one
‘value’ with the darker twigs and branches, and the light bands between of
one value with the interspaces of foliage transfused with skylight, against
which the branches and twigs ‘relieve.’

Another noteworthy detail of the independent efficacy of pattern is the
masking of birds’ and mammals’ eyes.* Markings of this kind occur chiefly
on predatory mammals, and on birds. See, for instance, the young plover’s
head in Fig. 67. Notice the dark ring surrounding the eye, and the longi-
tudinal dark mark at either end of it—a ‘stringing out’ of the eye’s dark
tone. Patterns like this, but often bolder and more varied, surround the
eyes of many birds and a few quadrupeds. The lengthwise stripe, especially—
the dark line which the eye seems scarcely to interrupt—is a very common
marking among birds. This seems to be a ‘conventionalized’ eye-masking
pattern, like the conventionalized ground pattern of larks and sparrows. It
is very effective, however, as it completely breaks the eye’s otherwise conspic-
uous circular or oval outline. Other, more varied patterns achieve this in a
still higher degree, often seeming to absorb the eye into themselves as one of
the details of their irregular form. (See Figs. 67-72.) Light-colored eyes,

* Many. herbivorous mammals have dark and lustrous eyes, surrounded by a more or less dis-
tinct pale-colored ring. This, however, belongs to the obliterative shading, playing its full part of
shadow-neutralizing when the eye is shut. Very likely the noticeableness of the open eye does the
animal good service when it is skulking, inasmuch as it increases the likelihood that the skulker will
know the instant he is surely detected by an enemy. All the rest of him is almost or quite ‘oblit-
erated,’ but there is still much chance that a predatory creature, hunting by scent as well as by sight,
may discover him. Because of this chance, he must be alert, ready to leap and run at any moment,
and must keep his eyes open, even though they may help to reveal him. But their very conspicu-
ousness increases the chance that the predator, having followed his quarry up by scent, or coming
suddenly upon it, will look first directly at those its points of vital watchfulness, thus giving it the
beneficent timely warning—the sure and instant signal that the crouching ‘ game is up ’—which would
be lacking if the hunting-beast first recognized some other portion of its quarry’s body. Encircling

marks and all, the eyes are small details of the ‘obliterated’ creature, and cannot attract the pred-
ator’s attention unless he comes almost within striking distance.

especially those with narrowly slit pupils, are often very inconspicuous, in
themselves. The green and yellow eyes of many felines, especially when they
are surrounded by irregular fur-patterns of about the same shade, are insid-
iously unapparent and elusive, ‘merging’ well with leaves and foliage-vis-
tas, etc. This obliterative coloration of cats’ and other predatory creatures’
very eyeballs must be a great aid to them in their stealthy stalking of their
prey. An eye like that of the Copperhead Snake (Chapter XXIV, Plate XT),
with its narrowly slit pupil, is as well concealed as any part of the creature’s
obliteratively colored body.

One more subject which must have a place in this rather miscellaneous
chapter is the coloration of birds in downy nestling plumage. Passerine
birds—most of them at least—are born naked and absolutely helpless, re-
maining in this condition for days. But they are almost always domiciled in
substantial nests, which in their turn are usually hidden amidst foliage, so
that the youngsters are well shielded from their foes. Such birds have no
true downy plumage, but pass from nakedness into a coat of frowzy contour-
feathers, marked somewhat differently from those of their parents, though
often much resembling them. But there is a great group of birds, including
most of fhe members of most of the orders outside of Passeres, whose young
are born with a full downy covering, which they retain for many days. Such
are the grebes, ducks, geese, gulls, terns, rails, shore birds, Galline (grouse,
etc.), goatsuckers, hawks, owls, etc. Of these the terrestrial (and aquatic)
forms concern us most, for they are more exposed to danger, and have more
highly developed protective co:oration, in the infant state, than the nesters in
trees. The terrestrial (and aquatic) assemblage may be again divided into
two sections, one including the species whose young are for a time sedentary
and helpless, and the other those whose young are active and alert from the
moment of birth, and leave the nest almost at once. Of the active sort are
grebes, ducks, rails, sandpipers, and .all the gallinaceous birds; while goat-
suckers, and, to some extent, gulls and terns, belong to the sedentary type.
Young grouse and other Galline acquire the power of flight, along with con-

~ Fie. 70. Killdeer Plover on its nest. [Cf. Fig. 71.]
Photographed from life by Dr, Thos. 8. Roberts. Courtesy also of *‘ Bird Lore.”

Fig. 71, Killdeer Plover over its nest. Obliterative shading, shadow-picturing patterns, ete.
Photographed from life by Dr. T. S. Roberts. Courtesy also of ‘‘ Bird Lore.”

Fic. 73. Nighthawk chick, as in Fig. 74,
Photographed from life by F. H. Herrick.

Fig. 72. Young Killdeer Plover,
wonderfully ‘obliterated’ by counter-
shading and ground-picturing pattern.
Photographed from life by Finley & Bohlman.

Fic. 74. Nighthawk (Chordeiles virginianus) chick—obliteratively-shaded d further ‘ Mal i
Sink Gistne aie 9 ) y , and further ‘merged’ into its background by blotchy

Photographed from life by F. H. Herrick. Courtesy also of G. P. Putnam’s Sons.

Fie. 75. Baby Conm-
mon Gulls (Larus canus).
Spotty ground-picturing
pattern, like theshadows
among pebbles, ete.

Photographed from life by
C. and R. Kearton.

Fic. 76. Baby _ Cur-
lew. [('t. Fig. 73.]

Photographed from life by
C. and R Kearton. Cour-
tesy also of Cassell & Co.

" Eis _" Young Crested Grebes. Highly-specialized obliterative picture-pattern (with obliterative
shading.
° Photographed from life by Cherry and Richard Kearton. Courtesy also of Cassell & Co.

Fie. 78. Bahy Red-breasted Mergansers (Merganser serrator). Fic. 79. Sketch suggested by
Water-shine-and-shadow patterns, etc. show how closely they represent a little wet spot in a swamp.

Photographed from life by Cherry and Richard Kearton.
Courtesy also of Cassell & Co.

the young mergansers in Fig. 78 to

Fic. 80. Young Horned Grebes on their nest. Obliterative shading and specialized ground-picturing patterns. [Cf. Fig. 77.]
Photographed from life by Herbert K. Job.

Fie, 81. Baby Woodcock (Philohela minor). Picture-pattern, based on counter-shading, Notice, here and in Fie. 82. Baby Woodcock
the next figure, the perfect picturing by these young birds’ patterns of dark holes and lighted details. (Philohela minor). (Cf. Fig. 81.]

Photographed from life by E. G. Tabor. Photographed from life by E.G.Tabor.

tour-feathers and elaborate picture-patterns, at a remarkably early age—
while they are still mere chicks—but with this and a few smaller exceptions,
there is much sameness in the baby plumages of the many members of these
widely separated orders. (See Figs. 67 and 72-76.) Pure obliterative shad-
ing is universal among them, occurring fully developed even in species whose
adult plumages lack it. Their color varies correspondingly to that of their
normal surroundings; those which are raised on the rocks, like terns and
nighthawks, being grayer, as forest-hatched grouse and whip-poor-wills are
browner; but there is a prevailing tone of dim-brown ground-color by which
the variations are connected. The patterns of these youngsters, too, are
nearly all much alike. Grebe chicks, young woodcocks, and some young
ducks, with their fantastic obliterative spots and stripings (see Figs. 77-82),
are exceptions; but most of the other kinds, from gulls to goatsuckers, wear
on their baby-down a soft, blotchy speckling, which seems to be the nearest
approach to a near-ground picture that the weak, hairy feathers can produce.
But this pattern serves admirably to merge the little, counter-shaded puff
of a chick into its immediate background of rock or pebbles or leaf-strewn
forest earth. The ‘obliteration’ indeed, strongly abetted by the chick’s
form-belying, ambiguous fluffiness, is often perfect. (See Figs. 48, 72, 74, and
82.) Young ducks and geese, living much among green reeds and grasses,
are more or less strongly tinted with greenish yellow, but their markings are
usually very simple. Baby plovers and sandpipers (Figs. 72 and 76) have a
dainty and effective pattern, though still more or less of the blotchily speckled
type, and are counter-shaded to a nicety; as are, indeed, almost all terrestrial
downy chicks.

CHAPTER XV

BIRDS. OBLITERATIVE COLORATION AND MASKING OF BILL AND FEET FOR
OFFENSIVE PURPOSES

NDER this heading I shall include the pattern-bearing ‘‘pantaloons”

of hawks, the prevailing pale or bright coloration and occasional

counter shading of their tarsi and feet, and the various bright colors and

occasional flowerlike appendages of the bills of jacanas, gallinules, anhingas,
herons, etc.

The spreading shields of leg feathers, or “‘pantaloons,” worn by almost
all hawks and some owls, and almost peculiar to them, must naturally be
supposed to have some connection with their predatory grabbing-habits.
But what is the connection—what the function of these pantaloons? One
use they have, and a seemingly important one, is this: they act as masks of
the dangerous talons, by making them appear merely as spots merged into a
moving veil of patterned feathers. If the extended legs and feet were stark
and narrow, without adornment, they would be much more clearly visible
to the animal attacked. As it is, the deadly feet descend in a broad and
blurring haze of mottled feathers, which must certainly reduce the victim’s
chances of successful dodging. The bold form of the hawk’s long leg is
veiled by these tufted feathers, and still further concealed by the pattern of
spots or transverse bars which these feathers bear. On some species, such
as the Rough-legged Buzzards (Archibuteo) of the North, and the Harpy
Hawks (Spizaétus) of South America, the entire tarsus is concealed by feathers,
‘usually covered with bold patterns (sharply cut by transverse barrings in the
Harpy Hawks); but most species have the tarsus as well as the foot bare for
action. Most owls, on the other hand, have everything but the very claws

muffled with feathers. The bare feet of hawks are usually very light in color
—yellow or livid green or orange,—oftenest yellow. These pale, bright colors
have a deceptive effect, inasmuch as they are less characteristic of hard ani-
mal substances than of leaves and flowers and grasses. Furthermore, they
tend to prevent the feet from looming darkly conspicuous, as they otherwise
would in the shadow of the body. In the case of the Osprey or Fish Hawk
(Pandion), whose spur-scaled foot has such a marvelous tenacity of grip,
Nature seems to have used her utmost skill in the manufacture of a perfect
fishing weapon. Not only are the tarsus and toes pale watery blue and green
in color, but there is even a perfect obliterative shading from the top to the
bottom of the foot. The pantaloons are obsolete, and all the leg feathers are
immaculate white—details in most evident harmony with the habits of the
bird. Spreading leg feathers would obstruct action in the water, and mark-
ings would be equally out of place, since they belong properly to the inhabi-
tants of the streaked and mottled realms of field and forest. Pure white, on
the other hand, is less conspicuous than any other tone or color when seen
from below against the sky, or against the body of the bird above, whose
interposed opacity additionally steeps the leg in shadow.

Of one class with these masking-devices of hawks’ legs and feet are the
bright and motley bill-colors of predaceous wading birds‘and swimming birds.
Whatever may be their other functions, these gaudy colors well serve to dis-
tort, conceal and mask the powerful beaks, to the vision of the fishes, frogs,
insects, etc., in the capture of whom they are employed. Some of these
beaks, such as those of many herons, of anhingas, etc., are marked with bril-
liant reed- and water-colors, in various forms and combinations. Others, such
as those of rails, gallinules, jacanas, etc., are like bright leaves, stems, or
flowers—green, yellow, orange, or scarlet, as the case may be, in varying pat-
terns, sometimes combined with water-like blues or purples. (Certain South
American frogs are clad in these same colors. See Belt’s ‘“‘The Naturalist in
Nicaragua,” p. 321.) Some of the jacanas have flat, erectile lobes or wattles,
of a rich red color, set about the base of the yellow bill, like red petals around

a golden corolla.* Many of these wading birds have also reed-colored or
otherwise deceptively painted legs and feet, which may often save them from
being snapped up by alligators and turtles, and must also help them in their
hunting.

The study of the colors of birds’ bills and feet in relation to their habits
and environments is a large field in itself, and we in this chapter have barely
peered over its borders. But there seems little room for doubt that the gen-
eral principles here briefly stated are dominant or at least very important
ones.

*Tt is most noteworthy that scarlet and yellow, the colors of the flowers and leaf stems of the
“cow lilies” which abound in North American swampy ponds, are also to be found on a great many
of the animals that resort to these places. The Wood Duck, the Gallinules, the Red-winged Black-
bird, and the Painted Tortoise, for instance, all wear scarlet, black (or dark blue) and yellow, just as
does the surface of such a pond, with its black shadows between the lily pads and flowers. Even
the long-billed Rails of the same region have (in spring and summer) coral-colored beaks. Indeed,
red, orange and yellow seem to be very common colors of aquatic vegetation and of swamp birds’
beaks, the world over.

From a hawk’s point of view, as he flies over swamps and ponds, it is not merely the black water
itself that these species match, but also the dark mud, and, in general, the dark spaces between the
vegetation. From overhead, the Red-winged Blackbird, even when perched on top of the bushes,
matches—or simulates—the shadowy spaces beneath; and his faintly discernible outline is easily
rendered indistinguishable by the conspicuousness of his scarlet and yellow cow-lily picture (just as
the letters in Fig. 106 are made illegible by their patterns)—in spite of his lack of counter shading.
In fact, though the ‘Redwing’ often perches high enough to show black against the sky, ¢o us, to the
soaring hawk he is commonly matched to the mud, as much as rails or coots.—A. H. T.

CHAPTER XVI

BIRDS, CONTINUED. ‘OBLITERATION’ BY IRIDESCENCE. CHANGEABLE COL-
ORS IN GENERAL; THEIR PART IN WATER-PICTURING COSTUMES, ETC.

RILLIANTLY changeable or metallic colors are among the strongest
factors in animals’ concealment, and go far toward achieving ‘oblit-
eration’ without counter shading. The quicksilver-like intershifting of many
lights and colors, which the slightest motion generates on an iridescent sur-
face, like the back of a bird or the wing of a butterfly, greatly obscures the
visability of that wing or back, as such, tending to make it ‘blend’ inextri-
cably with the gleaming and scintillating, labyrinthine-shadowed world of
wind-swayed leaves and flowers. Even without motion, the animal’s sur-
face, which would show all in its true place and plane if it were plainly col-
ored, is by its iridescence made to appear ‘dissolved’ into many depths and
distances. Here is a bright place that stands out near and clear, there a
dark area that melts away into“indefinite remoteness, and so on. Rarely does
such a ‘changeable’ surface, out of doors, reveal itself fully and truly to the
eye. Hence, iridescence is, as I have said, one of the prime factors of dis-
guise, and quantities of creatures profit by it. As a general rule, it is found
on animals that spend much of their time in lively motion. As we have seen
in Chapter XIII, the more minutely detailed forms of obliterative coloration
are not adapted to animals of this type. Seldom “‘lying close,” they need a
bold and simple disguise to lessen the conspicuousness of their movements.
This is found, as we have seen, in ‘ruptive’ pattern; and iridescence is equiv-
alent to ruptive pattern with an added gift—the power of motion. Ruptive
pattern, that is, with no fixed form, but mutable like the landscape itself.
87

When the iridescent-costumed animal is still, the slightest change of light upon
him will cause a bewildering play and movement of his colors; and when he
moves, his colors’ varied dancings are far more apt to belie and perhaps con-
ceal his motions, than to accentuate them. For instance, the gleaming high-
light, the central point of shine on the back or side of an iridescent bird, say
a turkey gobbler or a peacock, may move backward on the bird’s surface while
the bird himself moves forward, so that to the observer’s eye it seems to be
standing still, and since by virtue of its very brightness this spot will hold the
attention, it must often happen that the bird seems to be motionless when
he is in fact slipping away. It may be objected, and truly, that such decep-
tions as this are of only momentary effect. But the reader should realize,
in this case and in all kindred ones, that it is just these tiny, trivial seeming
moments that often tip the balance toward escape or capture, toward life or
death, in an animal’s career. The predatory animals and the animals they
prey upon have been developed together, and their powers of capture and
escape interadjusted to a nicety. The business of the one kind is to hunt
and kill, of the other to evade their clutches; both are Nature’s children, both
are favored by her, and both grow up and survive as races in the same woods
and fields. On the one hand, Nature fits the hunters to kill enough of the
weaker animals to keep themselves alive as a race, on the other she fits the
weaker ones to escape so often that their race too shall not succumb, that
the hunting race cannot overstep its boundaries; that, in short, the even bal- -
ance between hunters and hunted shall in the long run be maintained. On
the hypothesis of Natural Selection, we must suppose that there is the closest
rivalry between the two opposed developments; like the continual competition
which has long been going on in man’s domain, betweén the development of
armor and the development of explosives and projectiles. To their rivalry
alone is due the wonderful and ever-increasing excellence of both develop-
ments, in the case of the human instruments of destruction and defense; and
just such, if we believe in Natural Selection—or, in fact, on any hypothesis
that recognizes adaptation as something more than accidental—must we sup-
88

pose to be the way with predators and prey in savage nature. In any case,
it is obvious that, as things stand to-day, the very smallest items in aid either
of the hunters or the hunted must be of vital importance. Eagles and tigers
are not more clever at catching than their quarries are at escaping, hence the
slightest additional aid may save a quarry’s life. Just such an aid is the mo-
mentary deception effected by the contrary movement of a spot of iridescence,
as described above. Hindered but for an instant, the pursuer may be wholly
balked, for that instant may enable the quarry to slip into cover, or take wing,
just in the nick of time.

But the larger deceptions achieved by iridescence, viz., nearly complete
‘obliteration,’ in one form or another, are still more potent and important.
A brightly changeable plumage is like a sumptuous wardrobe, packed into
marvelously small compass—many different dresses combined in one, without
the loss of their individual identity. The Mallard Duck (Anas boschas), for
instance, has in some lights a bright green ‘‘speculum”’ on its wing. In other
lights this mark is blue, in still others, purple. In addition to the look of life
and motion (like that of water and glittering vegetation) which the change-
ableness of this marking gives it, it also makes it far likelier to match the
bird’s background than any fixed tint could. Water, mirroring whatever is
above it, varies interminably in color, and so do foliage-vistas and other land-
scape details. Were the Mallard’s speculum of a uniform blue, it would
serve its full obliterative use only when the bird’s background happened to
show areas of just that hue. But containing as it does the whole scale of
colors from grass-green to reddish purple, displayed one after another by
slight changes in the bird’s position, it is equipped for perfect color-match-
ing, if often only in flashes, with many sorts of background. Indeed, even in
most single views, and without motion, the speculum shows such a range of
lustrous color that some part is likely to be an exact match for one of the back-
ground tints. (Although this marking is usually almost hidden while the
ducks are swimming, it often comes into full view when they walk or stand,
as on river-banks or tussocks, or in reed-grown shallows.) Still more marked

and striking applications of the same principle occur among bright-colored
land birds, notably tropical ones. There are species with almost the entire
plumage highly iridescent, changing perhaps from bronzy red to emerald
green (or even to blue), according to the bird’s position relative to the source
of light and the beholder. Such for instance are some of those exquisite
aberrant kingfishers, the jacamars (Galbulide) of South America. One of them
at least, Galbula ruficauda, the only kind my father and I have studied in
its native forests, is exceedingly hard to discover when it is sitting stock-
still on its exposed look-out perch low down among the trees. It affects
semi-cleared areas, and the open reaches and borders of the forest, where
there is much variety in the colors of its background, and there is no dis-
puting the fact that its beautifully rich iridescence aids it greatly in escaping
notice in these places. Its colors shift with the shifting scene, as it were;
they counterfeit the airy life and changefulness of the encompassing leafy
landscape, played on and vivified by wind and sun and shadow, not to speak
of the changes wrought by the movements of the beholder. The environing
landscape contains, in one or another degree of purity and brilliance, all the
colors of the rainbow; and the tints of the jacamar’s plumage likewise range
through almost the entire spectrum. Often the bird’s background is bluish
green, often all his upper parts show nothing but that color; often, again, his
background is rich reddish bronze, just such as his feathers show in certain
other lights, and so on. Of course the changes in the bird’s color are inde-
pendent of the changes in his background, but in the long run his lively versa-
tility of tint must enable him much oftener to match his versatile background,
in part at least, than he could if his colors were unchanging. ‘The jacamar is
also a bird of the deep forest, however—not by any means confined to the
bright-colored half-open regions—and accordingly he wears on his underside
the regulation forest brown of tropical woodland animals. (See Chapter
XIX, p. 107.) If a bird wears colors characteristic of his environment, it is
not necessary for his concealment that he should momently ‘match’ his back-
ground, even in part. A spot of brown, for instance, introduced where such

a spot might well occur in the background, will readily pass for a real back-
ground-detail.

There are two kinds of changeable color among birds. One is iridescent
or metallic color, such as we have been considering, and the other, worn by
many of the most gorgeous species, is what may be called ‘dead’ or sheen-
less, changeable. In this there is no sudden glinting or intricate intershifting
of bright colors, but merely a change in the general tint of the lusterless and
uniformly-colored surface, dependent on the complete change of its position
relative to the source of light. This kind of coloration lacks all the subtler
magic of obliterative power possessed by iridescence, but shares to some ex-
tent its advantage of adaptability to often-varied backgrounds. Many of the
most brilliant blues, greens, and purples in the plumage of birds are of this
lusterless type. Good examples among familiar species are the common
European Kingfisher (Alcedo ispida), and the North American Indigo Bunt-
ing (Passerina cyania). When such a bird is between the beholder and the
source of illumination, its brightest color is a deep blue, or sometimes even
purple. When, on the contrary, the beholder has the source of illumination
behind him, and the bird in front, so that the light, striking it fully and fairly,
is reflected directly back to the eye, the parts which were before dark blue or
purple are clear, light green, sometimes even golden green or almost yellow.
(For the best effect, particularly in the display of the green extreme, the bird
should be seen head-on.) Some birds which are wonderfully inconspicuous
in their normal haunts have this type of coloration. Such for instance is the
American Purple Gallinule (Jornis martinica), mentioned in an earlier chap-
ter. The changeableness of this bird’s color, however, is mainly from bright
to dim, rather than from green to purple, and does not play a very important
part in his ‘disguisement,’ which is nevertheless adequate. It consists in a
close imitation of the beautifully blended tints of quiet water amidst luxuriant
vegetation. The soft purple breast and sides picture that part of the pool
which is shaded from the sky, and reflects almost nothing; the bright-blue
wing depicts the water which reflects the sky, and the green and olive back,

into which the wing’s color softly blends, is a perfect match for the dim reflec-
tions of vegetation at the water’s edge. Thus the Purple Gallinule’s costume
seems to be a picture of the entire surface of a little pool among the reeds.
It largely lacks obliterative shading, and its pattern is to some extent of
the ‘ruptive’ type, the ‘break’ occurring between the dark-purple underside
and flanks and the bright-blue wings. This makes the sky reflection seem
to stop short, as if against the shadow of a water plant, while the purple pic-
tures a darkly and graduatedly shaded portion of the pool. A kindred type
of coloration, but one involving true iridescence, occurs on the American
Green Herons (Butorides). ‘These birds’ costumes have perhaps even closer
affinities with that of the Wood Duck, described in Chapter XI. Both haunt
opener places than do the gallinules, not being dependent, as they are, on the
shelter of the reedy jungle. In this respect, however, the Wood Duck is in-
termediate between the other two, though nearer to the heron. Green Her-
ons frequent the reaches of open water, and avoid the reeds; but not being
swimmers, they are confined to the shores and shallows, and the trees and
bushes over them. Characteristically, then, they are birds of the edges of
small inland waters. Accordingly, we find them beautifully equipped with
water’s-edge colors and patterns. Their ash-green, delicately iridescent backs
picture the surface of still water, faintly shimmering, and covered with a film
of floating dust or scum, which blurs reflections. Their necks and heads,
- when brown (as in some of the species), match muddy patches on the bank,
or mud-holes seen through shallow water, or the interior brownness of the
trees and bushes over or beyond the water’s edge, or the brown, leafy ground
beneath them. But it is on the herons’ wings that the obliterative picturing
reaches its most elaborate development. Their ground-color is a soft, iri-
descent, water-green, and this is broidered over with a system of delicate
marginal stripes and bands of white and buff. These markings are so ar-
ranged that they imitate very closely the look of green-reflecting water rolling
in small ripples over golden sand—a most characteristic sight at the borders
of streams and ponds. The white marks depict the ripples, and the buff

marks the sand glinting through the moving water. Again, the system of
white and golden marks together simulates the flickering sun stripes on the
bottom, made by refraction from the ripples. Naturally, the life and realism
of these pictures are greatly enhanced by the iridescence of the green ground-
color.

There are a great many other beautiful cases of this use of iridescence in
aid of definite background-picturing, but the above example must suffice us
here. One more small detail, however, one more phase of the use of change-
able color, must be described. It is one to which I have already alluded, in
part, in this and an earlier chapter, namely, the apparent ‘opening of win-
dows’ in a dull-colored surface by the application of bright spots and stripes.
The brightest iridescent and sheenless changeable colors are often set in
spots like jewels in an otherwise dull costume. Common and important in *
the case of birds, this type of coloration is even more so in that of butterflies.
But these will be considered later, and we are here concerned with birds alone.
Many birds, particularly tropical ones, have such gemlike spots in the midst
of somber plumage. Often they are surrounded by dead black, or some
very dark tone of brown or gray. This encompassing dusky pattern, being
usually quite lusterless, is the same in all lights, while the bright spot in its
midst flashes and alters with every little shift of light or movement of the
bird or the beholder. Therefore it has the look of a hole in a motionless
dark obstruction—a glimpse through a somber shadow—beyond which are
seen sky vistas or the flickering light and movement of vegetation. Or, again,
the bright spots may pass for moving bits of vegetation relieving against a
motionless shadow or hole behind them. In either case, the solid form of the
bird will be effectually ‘cut to pieces.’

To sum up: changeable colors of all sorts strongly tend to conceal the
birds that wear them, and iridescence is extraordinarily potent in this way.
Its power is of two kinds, which are, however, practically inseparable in their
working. First, it goes far toward annulling the normal lights and shadows,
with their color-effects, of the surface on which it is placed; and second, its

great and vivid versatility of color and shade almost insures the ‘matching’
of some part of that surface with whatever forms its background. When part
of a bird’s surface blends thus with his background, the remainder, in most
cases, looks un-bird-like.

Tridescence should perhaps be considered second only to obliterative shad-
ing as a factor in the disguisement of birds; its universality attests its value.

CHAPTER XVII

BIRDS, CONTINUED. THE ‘OBLITERATIVE’ POWER OF APPENDAGES. ONE
USE OF LONG, BANDED TAILS CONJOINED WITH STREAKED BODIES

INCE the simple, organic outlines of an animal’s body tend to reveal it

to the eyes of enemies, Nature has resorted to many devices in order to
conceal those outlines. Such are various kinds of bold, contrasting patterns,
one of whose main effects is to hide the curved, characteristic forms by letting
into them, as it were, bays and notches of the background, of arbitrary shape.
Appendages are exactly the converse of this. They break the normal con-
tours by extending them irregularly outward, so that, figuratively speaking,
the animal is pulled out of shape and ‘bridged over’ into its surroundings.
‘“‘Appendages”’ include long tails, abnormally extended wing feathers, scap-
ular and other tufts, occipital crests, ‘‘beards,”’ etc., and also fleshy outgrowths
such as combs and wattles—in short, all superadded external developments,
whether of skin or feathers. Many of these devices must have a remarkable
concealing-power. Think for instance of the Mexican Quetzal, or Resplen-
dent Trogon (Pharomacrus mocinno), with its enormously long, green, droop-
ing tail. How potently delusive to a hawk, flying over a seated trogon, might
be this indefinite, smooth extension of its green back into the maze of leafage!
Other notable examples are the peacocks and pheasants. In the case of many
_pheasants an additional peculiar principle comes into play. Their long tails
aré marked with strong transverse bars, of two or more colors and shades,
like stripes of alternate light and shadow on dead leaves or earth, which tend
to merge the tails into their backgrounds when the birds are still, and thus
contribute largely toward their obliteration. (See Fig. 133, Chapter XXVII,
p. 238; Fig. 120, and Chapter XXTI, p. 159.) But when such a bird glides for-

ward, the bold transverse bars, being extended across the line of motion, make
the movement of the tail conspicuous, relatively to that of the longitudinally
streaked or finely speckled body ahead of it. By this device the bird’s chances
of escape from an enemy are decidedly increased. For the predator’s eye is
drawn to marks back of the vital part of his intended victim, which is at the
same time rapidly moving forward, hence there is likelihood that he will miss
his aim by striking behind, perhaps capturing a tail from which the bird tears
itself free and escapes.

The practical force of this law of the comparative conspicuousness of
transverse and inconspicuousness of lengthwise marks in motion can easily
be demonstrated. One should take a ribbon of cloth, or a slender board,
and mark half of it (one end) straightly and evenly with lengthwise stripes of
several colors (or simple black and white), and the other half with the same
colors in transverse bars. Then if the stick or ribbon is drawn smoothly
across an opening, through which alone it is seen, its motion will be grossly
visible while the banded part is passing, and almost invisible during the passage
of the striped half. Motion merely tends to convert lengthwise marks into
lines, which have little or no visible activity, and may often seem to be passive
streaks on the background of the thing that bears them. Hence the elusive-
nessof gliding striped snakes among sticks and grasses, in remarkable contrast
to the conspicuous movements of banded snakes. (Of this the reader is to
hear more in a later chapter.) A practical artificial test of this effect even
simpler than that above described, and almost equally effective, can be made
with a white string, part of which has been marked with dark spots, and part
left blank. The alternate light and dark spots are equivalent to the bands,
and the unspotted part is equivalent to the streaks (being, in fact, a single,
perfect streak). But the whole proposition is pretty much self-evident, and
scarcely calls for demonstration. As a factor in the protection of birds and
other animals the principle is of decided importance, and it very likely plays
a much larger part than we yet know. Among snakes and long-tailed birds,
particularly pheasants, its use is certainly both general and pronounced. On

the other hand, the application of such a principle in Nature is almost always
enmeshed and interwoven with that of other principles, and this case is no
exception to the rule. The same marks which serve to direct an enemy’s at-
tention to the tail when the bird is in motion, also serve, as we have seen, to
picture the quiet background when the bird is still. Here, however, we have
not the blurring counter-action of two principles, but their full codrdinate
development and perfect interadjustment. The marks on the bird’s tail may
be, and often are, beautiful pictures of leaves and sticks and light and shadow,
as potently obliterative as any other picture-patterns; this is their function
when the bird is “lying close.” But the moment he moves they are changed
into effective ‘target marks.’ The transformation is instantaneous and com-
plete; the picture-effect wholly ceases; for leaves and sticks and lights and
shadows are never seen to move off suddenly and rapidly over the ground,
in a compact, unchanging company. With patterns of lengthwise streaks, on
the contrary, there is little visible change between rest and motion, as we have
already seen. The longer and straighter are the streaks, the smaller is the
visible effect of their lengthwise motion, and vice versa. (The two extreme
types are of course connected by all manner of intermediates.)

Enormously developed feather-appendages are characteristic of several
groups of tropical birds, notably the Birds of Paradise (Paradiseide). Hith-
erto, it has always been supposed that male birds of paradise represented the
very acme of avian conspicuousness; but this belief is curiously wide of the
mark. Ina museum exhibition box, amid blank walls, one of these richly-
colored and sumptuously plumed birds is extremely showy and conspicuous;
but why should we infer from this that he must also be conspicuous in life in
his native woods? They are not monochrome and blank, but, on the con-
trary, full to overflowing with every possible variation of form and color,
produced by the redundant richness of the vegetation, and the numberless
vivid and changeable effects of sun and shade. The eye finds it hard or im-
possible to unravel such a luxuriant labyrinth, to separate and define the
boundaries of its individual components. Leaves and stems and trunks and

branches, vines, fruits, and flowers, shade and sunlight—all mix and overlap
and intertwine in the most bewildering way. Amidst, against, this intricate
tangle, even a simple bird-shaped bird, of uniform color, would be very incon-
spicuous; while a bird (like some of these birds of paradise) so adorned with
grotesque plumes * and bristling, ‘hay-stack’ tufts of superadded feathers as
to have lost almost all semblance of his simple bodily form, would be almost
insured against detection as he sat or moved in such a forest maze. His many-
colored plumose excrescences would serve with extraordinary efficiency to
blend him into his surroundings—here seeming to coalesce with a bunch of
gaudy flowers in sunlight, here with shining leaves, and there with a gulf of
somber shade. Then, too, all irregular outward extension of a bird’s form,
amid such surroundings, increases the frequency with which parts of his out-
line come into actual touch with like or kindred colored details of vegetation,
thus obscuring still more potently the bird’s real shape. (See Plate VI.)
The three main obliterative agents other than counter shading, which we
have now considered, namely, ‘ruptive’ patterns of boldly contrasting patches
of color, iridescence and other changeable color, and appendages, different
as they are in form, are yet closely akin to one another in the results they
achieve. In one degree or another, in one or another manner, they mask the
contour of their wearer, and ‘break him up’ into his background and sur-
roundings. Kindred in character, the three principles are often combined
in application, two or even all three of them frequently occurring in the same
costume; and the intricacies of their coadjustment are often very. hard to an-
alyze. In the case of certain birds of paradise, all three principles are found
in full codrdinate development. Male birds of paradise are well known to
have remarkable habits of raising and vibrating their plumes, as they sit in
small companies, among the females, in certain chosen trees. The observa-
tion of this habit has led people, most naturally, to believe that sexual dis-
play is the sole or at least the paramount use of the plumes and gaudy colors.

* Some of the big tufts of plumes terminate in such a filmy, hazy spray, that they can scarcely
fail, in any view, to seem softly blended into their background.

But the assumption that their use is limited to this one function is based on
the strangely mistaken notion that such birds are conspicuous in their native
woods. The error has been wholly based on theorizing—collectors have not
found the birds easy to see in their home forests, but, on the contrary, have
often testified to the strange illusiveness of certain very gaudy-kinds, even
relatively to their dull-colored and plumeless females. This has led to the
belief that they are conscious of being perilously gaudy, and are therefore
wary, and careful to keep themselves concealed amidst foliage, etc.—which is
evidently a complete misinterpretation of the case.

The question of how large a share, if any, sexual display has had in de-
veloping birds’ brilliant colors and elaborate appendages cannot be discussed
here. But we have at least shown that such developments, far from making
birds conspicuous, are all—pied-patterns, iridescence, and appendages—po-
tent factors in the concealment of their wearers. Even the lesser appendages,
such as small occipital crests, ear-tufts, wattles, etc., all tend to conceal birds
by breaking their normal contours.

99 :

CHAPTER XVIII

BIRDS, CONTINUED. MISCELLANY. MIMICRY AMONG BIRDS. THE BRILLIANT,
FLOWERLIKE COLORATION OF HUMMINGBIRDS’ HEADS NOT MIMETIC.
SEXUAL DIFFERENCES OF COLORATION

WO kinds of ‘Mimicry’ have been described by various authors as oc-
curring among birds; first, the form distinguished as ‘‘ Protective Re-
semblance,” in which a live animal counterfeits the appearance of an inani-
mate thing, and second, so-called Mimicry proper, in which one animal
counterfeits the appearance of another. But of Mimicry proper among
birds few instances have been cited, while Protective Resemblance has been
supposed to cover most branches of avian (as well as mammalian, insectile,
etc.) protective coloration, including the many which we have already shown
to belong to the very different principle of obliterative coloration. The ques-
tion of “protective resemblance,”’ :
mate things—is somewhat closely involved with certain phases of the oblit-
erative coloration of birds, and must be considered here. I have mentioned
it several times in the preceding chapters, in connection, for instance, with
bitterns, goatsuckers, ruffed grouse and screech owls. In all these cases,
the principle has either been dismissed as having no true application, or has
been shown to be subordinate to the laws of obliterative coloration. The
ruffed grouse and the screech owl draw their feathers tightly to the body,
making themselves as thin and sticklike as possible—and this might be
called mimicry. But, as I have explained, this very action is essential to the

indeed—the mimicry by animate of inani-

perfecting of their exquisite picture-patterns, which imitate the details of their
more or less distant backgrounds, rather than the markings on a single fore-
ground branch or stub. ‘The bittern, likewise, with head and neck held stiffly
upright, might be supposed to be mimicking a stick, but a more critical in-

100

spection reveals the fact that his head and neck picture several reed stems,
with their shadows, and that the peculiar attitude is necessary for the most
effective display of this obliterative or at most semi-mimetic pattern. (Semi-
mimetic, inasmuch as the several reeds seem to occupy about the space really
filled by the bittern’s neck, although the effect is still of the neck’s dissolution
into its general background and surroundings.) But in all or most such cases,
in spite of the evident paramount importance of the obliterative function, it is
undeniable that the mimetic effect is sometimes achieved, to a greater or less
extent, and hence that it must be a factor in the development of the peculiar
actions and even the particular coloration of certain birds. Just how large
or how small a factor, who shall say (?); but recognizing the dominant impor-
tance of the obliterative laws even in these few special cases, one cannot sup-
pose that the other principle has more than a very limited and slender scope.
Nevertheless, it is not to be ignored. A Ruffed Grouse picking buds high
up among the leafless twigs of winter trees, must often be seen in a light and
against a background (as of blank snow) which does not favor its obliterative
coloration. Then the extraordinarily slender, stick-like form (accentuated by
peculiar angles in the head and neck, and by the erected occipital crest) which
the bird assumes the moment it is alarmed, does certainly render it good ser-
vice in the direction of protective ‘mimicry.’ At such times the bird’s ene-
mies must often mistake him for a knotted branch. Yet, on the other hand,
even at such times, thanks to the bird’s perfect obliterative shading and pat-
tern, the chance is great that he will not be seen at all (as a solid object), and
this chance is probably still of paramount importance.

But there is one bird at least in whose case the balance of importance may
tip toward the mimetic function of specialized perching-habits. This is the
big woodland goatsucker of northern South America, etc., the ‘“Poor-me-
” of Trinidad negroes (Nyctibius jamaicensis), whose characteristic
perching place, both by day and night, is the top of a broken stump or up-
right branch. Here it sits almost erect, and motionless, with its long and
ample tail pressed flat against the side of its perch, which seems to be con-

IOI

one

tinued upward by the bird’s dark, obscurely mottled body, terminating in the
broad, flat head. This mimetic attitude is completely effective in the twi-
light or moonlight, when the ‘‘ Poor-me-one” uses a stump-top as a look-out
perch, whence it launches forth on short flights after aérial insects, soon
sailing back to cap the same or sometimes a neighboring stub. There can be
no doubt as to the completeness and importance of the mimetic function of
the ‘“‘Poor-me-one’s” peculiar perching-habits. The mimicry, however, is
mainly positional, or attitudinal, for it is not supported by any very particular
developments of the bird’s form or markings. The bird’s mottled pattern,
to be sure, is less exquisitely fine than that of many nearly related goatsuckers,
and hence less well fitted to serve the full obliterative function of background-
picturing, while it must greatly help the stump-top mimicry, especially in a
dim light. ‘‘Poor-me-ones”’ have been found roosting in the daytime on the
tops of stumps, in the characteristic erect attitude, and in these cases they
were certainly “‘making a bid” for mimicry, in which both color and mark-
ings played a part. But it is likely that their roosting-habits vary somewhat,
as I know that their nocturnal perching habits do. They have a strong pref-
erence for naked stumps, but I have more than once seen them sitting in the
moonlight on horizontal leafy boughs, and even perching lightly among the
slenderest twigs at the very tips of the branches. Assuming that there is
equal irregularity in their diurnal roosting habits, as we may pretty safely
do, it follows that they must often be so situated that the obliterative function
of their coloration comes fully into play. Indeed, there can be no doubt of
this, as they are equipped with a complete, though slight, obliterative shading,
which hinders rather than helps the mimetic effect; and their markings, though
relatively somewhat crude, yet partake largely of all the elements of back-
ground-picturing. But, from all that we yet know of the habits of this in-
teresting bird, it seems probable that it profits at least as much by out-and-
out mimicry (in effect) as by obliteration. This is the most pronounced case
of the kind that we happen to know of. Others equally remarkable exist,
no doubt; but they are rare enough to be fairly called anomalous. On the
102

other hand, the cases are many of the occasional mimetic aspect of birds
whose main protective equipment is purely obliterative, like the ruffed grouse,
screech owl, etc., just referred to, and the terrestrial goatsuckers mentioned
in an earlier chapter. Other slight and dubious encroachments of mimicry
into the domain of obliterative coloration have been mentioned here and
there in the foregoing pages, as for instance in connection with the flowerlike
bills and frontal appendages of certain water birds (Chapter XV).

The gorgeous “‘beauty spots” of hummingbirds, most commonly occurring
on the head and throat, are certainly not mimetic, though they have some-
times been considered so. Flowerlike though many of these brilliant head-
dresses are, there is not, I believe, one among them all which really imitates
a single flower, in minute and near detail. On the contrary, they are all
flashing pictures of flowery and leafy landscape, at uncertain distances. Hum-
mingbirds’ metallic colors mark the very climax of the development of iri-
descence, the high obliterative power of which principle has already been ex-
plained. Their changeableness often ranges from dull, velvety soot-color to
the intensest gleaming of pure red, blue, green, orange or purple, as the case
may be; and sometimes several of these bright colors coexist in the same
feathers, showing either separately, in different lights, or intermixed, in one
light. But the change from one bright color to another is less characteristic
of hummingbirds’ iridescence than the change from dull black to keenest
brightness. It is in the fullness of this change, and the extreme brilliancy
of the high-light tints, that the supremacy of their coloration lies. Perhaps,
after all, they do not quite deserve the palm for iridescence, in the strict sense
of the word, but for changeable and luminously brilliant color, they are almost
unique among animals. Indeed, they have an almost unrivaled obliterative
equipment. Behind the dazzling, scintillating blaze of its jeweled head, how
can the little round body of a hummingbird be seen? ‘That shifty blaze of
red or green or purple light, one instant partly clouded over, and in the next
flashing out into the sharpest sunlike sparkles, completely eclipses and masks
the form and solidity of the body, now veiling it, and now piercing it, so to

103

speak, with all manner of rents, and vistas of its brilliant, sunlit background,
utterly bewildering to the beholder.

It is a noteworthy fact, and an interesting theme for study, that the bright
colors of almost all hummingbirds are only revealed, or at least Only revealed
in their full power, when the birds are seen head-on and facing into the light.
This is true, indeed, with many other birds of changeable color, but in no
other group is it nearly so marked as among the hummingbirds. Many of
their brightest “‘beauty spots” are dead and dusky except in full front view
and lighting. This fact has an interesting bearing on the question of the
special uses of hummingbirds’ glorious plumage, and suggests several addi-
tional possibilities. One of these is that their obliterative coloring is ad-
dressed primarily to insects on the flowers and leaves before which they hover,
and is therefore offensive rather than defensive. Hummingbirds are so small
and lightning-swift that it must be nearly impossible for any predatory birds
or beasts to catch them. ‘Tree lizards and small hawks may occasionally
seize them while they are perching, although they usually (?) sit on bare,
isolated twigs, and are extremely watchful. This watchfulness, however,
seems to be directed mainly against other members of their kind (i. e., other
hummingbirds, of whatever species), and is aggressive rather than defensive.
They are, as is well known, extraordinarily pugnacious, and where several
congregate they are continually chasing one another. Nor is this strange —
animosity exercised solely against their own kindred; with equal frenzy they
dart at flycatchers, hawks, eagles,—any flying bird, either big or small, that
enters their domain. On the whole, it must be assumed that they enjoy a
comparative freedom from the dangers that beset most of the smaller birds.
Yet their obliterative equipment is among the finest, and must be of great im-
portance to them. The effulgent, steely brightness of their head-colors, often
extended outward by erectile tufts and crests, and showing only in full front
view, undoubtedly serves to ‘veil’ them from the sight of insects lurking in
and upon leaves and flowers. Without such adornment, the birds would
loom up darkly solid between their little victims and the light, thus warning

104

them and giving them a moment’s grace for taking flight or crawling out of
reach. But their marvelous headgear masks their menacing solid forms.
Irradiated, as it often is, by sunlight, it matches the bright, gaudy back-
ground of flowers, leaves and sky, piercing and obliterating the interposed
bird-bodies. As, from moment to moment, the bright real scene beyond
flashes and twinkles and changes, so the mock scene on the hummingbird’s
front sparkles and shifts with his every slightest movement, and every flicker
of the light that vivifies it.*

It is needless to discuss here the meaning of hummingbirds’ many re-
markable appendages, inasmuch as the high obliterative value of such de-
velopments in general has already been explained.

Male and female hummingbirds are usually unlike in plumage, and their
differences correspond to those of most other forest birds. Furthermore, they
are in close and evident accord with the differences in the habits of the sexes.
The female sits on her neat, moss-trimmed nest, in a shady place, while her
mate is buzzing around among the flowers and sunbeams. The bodies, even
of the males, are usually equipped with obliterative shading, and the females
almost always have it in full development. They are dim in color, relatively to
their mates, being mainly soft (but often metallic) green, brown, or gray,
and rarely having any fully developed gemlike spots or plumes,—all of which

* A probable minor function of this flashing headgear, under the very same conditions, is the
illumination, by reflected light, of the calyxes of flowers, and the shaded sides of leaves, which the
hovering hummers probe and search. They carry, as it were, little colored lanterns on their heads,
whose disk of blue or green or red or purple light can be thrown deep into a tubular flower, or moved
up and down and back and forth across a dusky leaf. When any of the very bright ones among these
gaudy little ‘reflectors’ are played on by bright sunlight, and headed more or less directly sunward,
they cast a really illuminating glow, which can scarcely fail to be of service to the hummers in their
insect-hunting. Again, it is likely that the flaming head-dresses of these little birds—as also the erec-
tile crests of flycatchers—sometimes act as “‘war paint.” When a male hummer leaves his hovering
and perching amidst flowers, where his colors are potently obliterative, and launches forth into free
air, often above the tree-tops, in violent pursuit of another bird, his fiery-flashing brilliance may
well codperate with the arrowy vehemence of his attack in frightening the object of his anger. Far

oftener, however, it must tend rather to dazzle and stupefy the persecuted bird, and, by its incessantly
varied gleaming, to bewilder him as to the exact position of the chaser.

105

is in evident harmony with their habits. For, as with other female birds, one
of the most critical periods of their lives is the time of brooding, when, hour
after hour and day after day, they have to sit on top of their open nests, in
quiet, steady-lighted nooks. Even when, as is usually the case, the females
as well as the males feed in the gay, sunlit upper border of the forest, they
descend into the shady underworld to nest. Hence the fitness of their being
softly colored and delicately counter shaded, while their mates are adorned
with magnificent jewel-spots and strange appendages. In this matter hum-
mingbirds will serve to exemplify the whole group of forest birds in which
the sexes are decidedly unlike. The female, almost without exception, is
colored and shaded in the way which best conceals her while she is brooding;
whereas the male is colored for active life among the leaves and flowers.
Corresponding sexual differences of habits and plumage occur among other
than woodland birds. Those of ducks I have already mentioned.

106

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CHAPTER XIX

BIRDS, CONCLUDED. VARIOUSLY INVOLVED PRINCIPLES OF PROTECTIVE COL-
ORATION OF THE BIRDS OF TROPICAL FORESTS. WINTER BIRDS OF
THE SNOWY NORTH. CONCLUDING REMARKS ON BIRDS

HE dim, brown underworld of tropical forests is tenanted by a race of
birds and beasts which show a wonderful uniformity in coloration and
degree of counter shading. The daylight in these solemn depths is diffuse
and weak; hence the animals which live in them are as a rule very slightly
shaded from dark to light, and many have pale-brown undersides. Brown
is their prevailing color, and there is one particular tone of rich chestnut-brown
which occurs almost unvaried on many hundred species. Such sameness of
coloration is remarkable; but it is in perfect keeping with the monotony of the
realm in which the creatures live. Almost nowhere else can one find such a wide-
ly extended prevalence, throughout the year, of a particular degree of light and
a few simple tones of color, as exists inside the shell of the great tropical forests.
On the outside of that shell everything is different. There, in the blazing
sunshine toward which the closely crowded trees and vines are ever struggling,
the victors heave their leafy heads, flashing and dancing with a thousand tints
of gold and green and sky-reflected blue—jeweled with gorgeous fruits and flow-
ers. In this gay realm of scintillating lights and colors live almost all the bril-
liant birds and butterflies, for which the tropics are famous; and they are as
closely fitted to their environment in colors and patterns as are their dull-brown
relatives of the somber shades below. The tropics are as rich in dull-colored
birds and butterflies as in bright ones; but the dull kinds are not often collected
and exported except by naturalists, and do not attract popular attention.
The transition from the tree-top to the ground type, in habits and in col-
oration, is beautifully gradual and consistent. Blue—clear, skyey blue—
107

plays a large part in the costumes of the true tree-top perchers. (Vide, in our
northern American fauna, the Indigo Bunting and the Bluebird.) With it are
combined red, green, yellow, and all the other bright colors, in sharp ruptive
patches, picturing, in general, the sunlit forest crown seen from above. One
step below these ‘perchers in air’ live the skulking tree-top birds, as it were
the rails and gallinules of the forest’s crown. These live among and beneath
the outermost leaves, immersed in a deep bath of green light; and many, though
not all of them, are mainly or wholly green. Such, preéminently, are the
parrots, those queer and splendid geniuses of the tropic woods. They crawl
about through the forest’s crown, and comparatively seldom sit on bare,
high perches. When they do so they are of course inconspicuous enough
against the tree-tops; but many of them lack the finer developments of sky-
matching and more generalized background-matching costume. Instead
they are attired to match the leaves and flowers among which they are feed-
ing. ‘They are obliteratively shaded, almost all of them, but faintly, in keep-
ing with the diffuseness of their usual leaf-dimmed illumination, and their
acrobatic feeding-habits, which put them into all sorts of irregular positions
relative to the sky-light. There is almost certainly a significant connection,
too, between their habit of feeding head-downward, and their gayly blossom-
colored tails. Poked up above the feeding parrot’s line of watchfulness, and
often into the stratum of gaudy flowers and fruits, this tail must have the
best possible disguise if its owner is not to be pounced upon from above by
some swift hawk. So it is done out into brilliantly disruptive and oblitera-
tive spots and patches of rich flower- and fruit- and sky- and sunlit- foliage-
colors,—‘‘conspicuously ornamented,” as people used to say. In fact, it is
doubtless, under the normal, appropriate conditions, a very mask of masks.
Fitly colored for inconspicuousness above the ‘green-bath’ region, it is
scarcely less so for the midmost recesses of that region itself, because the all-
suffusing greenness greatly dims the brightest contrasting hues, bringing the
red, yellow or purple patches of a gaudy-motley bird nearly or quite into
unison with the variations of interior vegetation colors. Thus it is not strange
108

that some of the typically ‘skulking’ tree-top haunters of the tropics are
most gaudily ‘patched,’ more so even than the parrots, and that many of
the brightest colored ‘high-perchers’ spend much time fairly amid the foli-
age. But pure leaf-green is the prevailing color of the tree-top foliage haunt-
ers, just as rich brown is that of the forest ground birds. Between these two
types again there are perfect intermediates. Such is the motmot, with its
ground-brown underside, its soft green back, and its black and bright-blue
head; such also is the beautiful jacamar, described in Chapter XVI (p.
go), and such are some of the dim-colored, low-ranging hummingbirds.
The toucans, also, with their great amount of sharply defined black, are best
fitted for obliteration in the intermediate woodland realms, where darkly
shadowed big branches and tree trunks contrast with sun-spots and gay vis-
tas. But they are also tree-top birds, high-perchers, and their vividly patched
costumes of course stand them in good stead in these situations also, in spite
of the redundant black. This usually covers the head, back, wings and
tail; while the underside is marked with big patches of bright color—red,
orange, yellow, white—sometimes all four together—more or less blended into
one another, but ending sharply against the black. The huge but almost
weightless bill also is brilliantly adorned with yellow, white, or flaming orange,
in bold bands and stripes, and the naked skin around the eye is usually
bright colored—blue-purple, peacock-blue, or green. Truly, toucans are
gorgeous birds! But it by no means follows that they are conspicuous in
their native woods! Not even though they are vociferous and active, and
often alight on exposed tree-top perches. Here or lower down in the forest;
their gaudy ‘ruptive’ patterns ‘break them all to pieces,’ and though the
predator at whose approach they ‘freeze’ into rigid stillness may espy the
black piece, or the red piece, or the yellow or the blue piece, he is still far
from sure to recognize his quarry, for none of these pieces has the form of a
bird. So with the colors of the tanagers, the birds of paradise, the macaws,
and all the rest of the brilliantly pied tropical forest birds, many of which
range, like the toucans, from the upper border of the forest underworld to

109

the airy tree-tops. The frequent black in their costumes, though it often
fits in very well with their tree-top background-picturing and ‘ruptive’ pat-
terns, seems on the whole to be a concession to the time they spend among
dark trunks and branches fairly within the forest. Practically all these party-
colored tropical birds have counter shading, in the main relations of their
colors, however much its smooth gradation is broken and interrupted by the
bold patterns, and however irregular and acrobatic may be their feeding-
postures. The multiplicity and variety of bright-colored vegetable forms in
the sunlit crown of a tropical forest make a great variety of ‘ruptive’ pat-
terns and colors effective for the disguisement of its birds. As has been told
in an earlier chapter, ruptive patterns are often intricately commingled both
with iridescence and with appendages, all three factors working toward the
one end, ‘obliteration.’ It is in the tropics,—in the tree-tops and in the forest-
borders—that we find the highest development of all three principles, both
separate and combined. Iridescence is not second in importance to ruptive
pattern, nor is it less widely and variously used. Appendages also play a
very important part, as we have shown.

One more component principle of ‘ruptive’ coloration, prominent in the
costumes of tropical wood-birds, must be here explained. This is the fre-
quent juxtaposition of complementary colors. Just as brilliant iridescence
tends to range from one color to its full opposite, or ‘‘complementary”’—as
from red to green—so, when two bright colors occur side by side in a ruptive
pattern, they are usually not kindred, but complementary. Thus we find
green-breasted trogons with red bellies, purplish-blue-breasted trogons with
orange bellies, orange-yellow tanagers with steel-purple backs, and so on.
Not only are the colors thus placed intensified by mutual contrast, but, by the
very added sharpness of their difference, the ‘disruptive’ effect is heightened.
The opposed patches seem less than ever to belong to one and the same ob-
ject. A bright color tends even to create its complementary.* Look at a
rich yellow flower, or some other small yellow object, against white paper.

* See the footnote on p. 19, Chapter I.
IIO

‘The white next the yellow seems to glow with purple, yellow’s opposite. By
the same token, two actual complementary colors side by side are much more
powerfully brilliant than two kindred ones so placed. ‘This law has yet other
bearings on our present subject. It tends to explain the otherwise somewhat
anomalous bright red of certain strictly foliage-haunting birds, like the sev-
eral tanagers and trogons. How can such birds, living almost always among
green leaves, in a bath of green light, profit by wearing the most vivid red, the
diametric opposite of foliage-color? The answer, im part, is this: dimmed
by the strong bath of green light, the bird’s red, actually brilliant, looks barely
brighter than many of the glowing brown interstices, the paler shadows on
dead leaves, twigs and tree trunks amidst the verdant foliage. Even brown
dead leaves most favorably situated for showing off their color amidst live foli-
age are brighter than bright-red tanagers or trogons least favorably situated
for display against a like background. Also, there are, commonly, many dis-
eased leaves amid the foliage with red as bright as the birds’. But there is no
denying the fact that some of these birds, for instance the northern Scarlet
Tanager, are more conspicuous in the green woods than their foliage-colored
kindred. On the other hand, again, it is true that bright, strongly contrasted
hues, and red among the rest, well serve to produce ‘ruptive’ effects in the
color-neutralizing, deeply green-steeped light of the leafy labyrinth in which
such birds live, where dimmer tints could not hold their own. This is the way
with the beautiful red-and-green trogons, which are by no means easy to dis-
cover in their native woods, though vociferous and tame. In tropical as in
temperate woodlands, however, the smaller gleaning birds and flycatchers of
the shaded lower leafage are characteristically green and yellow and olive,
without very bold markings. They live fairly hidden amidst shaded foliage, so
that dim leaves in a near view, undiversified by other landscape-details, form
their normal background. In his admirable paper on the birds of Trinidad.
at the mouth of the Orinoco River,* Mr. F. M. Chapman, the American nat-

* “On the Birds of the Island of Trinidad,” Bulletin of the American Museum of Natural His-
tory, vol. vi, 1894.

ITI

uralist, has two pages of very interesting discourse on the color relation be-
tween birds and their surroundings in the wild-woods of that island. He
fully saw and described the distinctness of the three main color-classes of trop-
ical forest birds, the brown, the green, and the gaudy-motley, each with its
own appropriate local habitat. Much of what I have said on this immediate
theme is scarcely more than an echo of Mr. Chapman’s words, though based
on our own subsequent investigations in the same island forests. Limited as
they are in extent, the primeval woods of Trinidad are doubtless fairly repre-
sentative in character of the great South American tropical forests, and, by
the same token, of all the humid tropical forests of the world. For, as we
learn from traveled naturalists, tropical ‘‘high woods” are all much alike in
their main general characteristics. Just how largely this likeness extends to
the general habits and disguising-equipments of the forest birds, we, person-
ally, cannot say; but there is every reason to suppose that the main principles
are the same among the birds of tropical Asia, Africa, and Malaysia, as among
those of tropical America. Indeed, a study of tropical birds in museums, and
of the writings of naturalist travelers, leaves one with little doubt on this
score. .

In the matter of local habitat, Chapman divides the forest birds of
Trinidad (and hence of all tropical America) into five groups, namely, those
of the tree-tops, those of the shaded foliage below the tree-tops, those of
the tree trunks below the foliage, those of the bushes and scrub at the for-
est’s border, and those of the ground. The first and second groups comprise
respectively the gaudy and the green birds, as has been told. The three
remaining groups Chapman lumps as brown birds. This will do for a very
general classification, but it seems to me that while the scansorial and ter-
restrial species may well be classed together, the scrub birds should be sep-
arated from them. For, many of these scrub-birds, as Chapman intimates,
lack the characteristic forest brown, or have in addition a large share of other
colors. Their ‘class,’ however, is laxer and more irregular than the rest,
and its special characters are harder to define. Both in habits and in colora-

112

tion, its species grade into other classes, not only of forest birds, but of the
birds of the open land, the reed swamps, bush swamps, and river banks, where
still other systems of coloration come into play. Thus there are ‘brush-
birds’ which have also a liking for spots of bare, open ground, and have ac-
quired markings much like those of larks and other field birds of the North.
Characteristically, however, they are somewhat boldly mottled, with much
black and white and ash color; ‘pictures’ (to be seen in the dim light of the in-
teriors of bushes) of sky vistas overlaced with obstructing, shadowed leaves
and branches. Some of those which frequent river banks, like certain Ant-
birds of South America, are often marked with the water-shine punctations
described in Chapter XI, on a ground-color of muddy gray or brown, oblit-
eratively shaded. But the vagaries of this none too sharply defined class
cannot be described in detail here. The species which constitute it are less
typically birds of the forest than of the brush-lands outside the forest. Nor
are they, as a color-class, peculiarly characteristic of the tropics, being scarcely
separable from the brush-birds of temperate climes. True, the brown, green
and gaudy classes are also represented in northern woodlands, but by no
means in such full and special development as they have attained in the teem-
ing tropics.

In the snowy northern winter, on the other hand, where the avifauna is
extremely meager, we see special color-adaptation reduced to its simplest
terms. The costumes of the few birds which pass the winter in the snowy
northern: forests, deciduous or evergreen, are, it is evident, specially fitted
to that season of the year. Some of these birds even, like several of the boreal

“mammals, turn white at the approach of winter, resuming their gray or brown
mottled plumage in the spring. Such are the ptarmigans, described in Chap-
ter VII. But most of the species either keep the same coloration throughout
the year, or merely become somewhat paler and dimmer in the autumn, grad-
ually brightening, by the erosion of the feather-tips, through the winter and
spring. But even those which do not change color are best equipped for con-
cealment in the winter—the dangerous time of leafless woods and keenly

113

hungry birds and beasts of prey. One of the most patent signs of this is the
great prevalence of white in their costumes. The Snowy Owl, for instance,
the chief rapacious bird of the high north, is white (more or less profusely
flecked or barred with sooty brown) throughout the year. During the few
weeks of arctic summer, when it hunts and nests on mossy, treeless tundras
or barrens, it must be a conspicuous ‘object when seen from above against
the ground (although even then it may often be mistaken for a scrap of lin-
gering snow or ice). But it has little or nothing to fear from predaceous
enemies, and its summer diet consists chiefly of lemmings and other small
mammals which live on the open ground, so that the owl always appears
above them, against the sky; hence white serves it as it serves the seafaring
terns and gulls (Chapter XII) and the partly white-masked mammals to
be described in a later chapter. Another northern bird, colored almost
exactly like the Snowy Owl, and with kindred habits, is the White Gerfal-
con. In addition to these more or less predominantly white birds (ptar-
migans, owls, and falcons), many of the smaller species of the winter North
are largely marked with white (irrespective of their obliterative white under-
sides). Noteworthy among these are the woodpeckers, titmice, some of the
Fringillide, and two or three of the Corvide (namely, the magpies and the
North American Blue Jay). Most of them wear a pied or boldly speckled
pattern of black and white, which reaches its highest development on some
of the woodpeckers, as the Hairy and Downy (Dryobates villosus and D.
pubescens) of America, and the Great-spotted and White-backed (Picus
major and P. leuconotus) of Europe. These woodpeckers are in fact cov-
ered with adequate generalized pictures of bits of winter landscape, where
dark tree trunks and branches relieve against the snow or sky. Fig. 83
(photographed from a picture made by combining a real Hairy Woodpecker’s
skin with a painting of a winter-forest landscape) will tell the reader more than
many words. Even in summer, though less wonderfully fitted to the land-
scape, these woodpeckers are far from being conspicuous birds. The larger
outstanding spots of white still often pass for glints of sky seen through the

114

Fie, 83. Hairy Woodpecker (Dryobates villosus) in winter woods. [See p. 114, Chap. XIX.] Photograph
of a stuffed skin against a painted landscape. Scene copied, ‘tone’ for ‘tone,’ not from the woods, but from the
woodpecker. The reader must judge for himself as to its realism.

forest, while the smaller ones, and under some conditions the larger ones too,
produce a mottled effect much like that of the tree trunks on which the birds
climb. (See Chapter VIII, p. 50.) Significant in connection with the evident
winter-picturing in the costumes of these northern woodpeckers is the differ-
ent coloration of their southern relatives. The Downy and Hairy Wood-
peckers are distributed from the southern United States almost to the northern
limit of tree-growth, and being non-migratory, have developed certain geo-
graphical racial differences. The birds of the northernmost race are biggest
and whitest, those of the southernmost, smallest and blackest. Other species
of the same genus, and of nearly allied genera, which are peculiar to the
southern part of the country, below the limit of snow, lack the larger white
blotches, being for the most part closely barred and speckled, in ‘tree-bark
patterns.’ The Golden-winged Woodpecker (Colaptes auratus, etc.), which
is mainly brown and black and yellow, abounds in the northeastern United
States during the summer, but migrates southward in the fall, for the most
part keeping outside the snow-line. Looking still farther south, to the Amer-
ican tropics, we find the woodpeckers brown and red and yellow and gray
and olive, and, with a few exceptions, almost entirely devoid of white. Many
of the tropical woodpeckers, indeed, and their allies in habits the Wood Creep-
ers (Dendrocolaptide), belong strictly to the class of tropical ‘brown birds’
described earlier in this chapter.

The northern tits and nuthatches are colored much like the northern
woodpeckers, but in simple, bold, undiversified ‘ruptive’ patterns. (See
Fig. 61.) So also-with the magpies, which have the added gift of rich irides-
cent color in the tail and wings,—picturing snow-shadows and fir foliage.

The costume of the beautiful Blue Jay (Cyanocitta cristata) is a wonderful
picture of a winter landscape—snow in shadow, snow in sunlight, sky, trees,
and vinous-gray scrub—all are there, in true and exquisite comminglement.
Here again we have a picture to show in aid of unconvincing words. The
Blue Jay picture in Plate VI, unlike the woodpecker figure, was painted
from bird-skins against a real out-door background. Of course the Blue

115

Jay’s costume is not confined to this one kind of background-matching. It
pictures, perhaps equally well, a much nearer bit of snowy ground, thickly
fretted with blue shadows, with some dark twigs or branches relieving against
it. Wherever the bird alights in the winter woods, he looks like a vista through
the tree in which he sits to one or another of these blue and snow-bright back-
grounds. He bears a full obliterative shading (from dark blue and black to
white), without which the delicate distance-picturing would be impossible. In
summer the Blue Jay’s perennially unchanged coloration is less closely fitted
to its environment; but the bird is never conspicuous. The blue, seen in
the leafy sylvan dimness, is usually soft and dull, and not sharply differen-
tiated from the vinous ash-color of the breast and flanks; the white spots, as
in all such cases, picture glints of sky, or lighter leaf-vistas; while the dark
marks look like sticks and twigs and holes and shadows. (See Fig. 60.) Or
again, when the clear, light blue of tail or wings gleams out with especial
brightness, it may pass either for sky-shine on the leaves or for a bit of blue
sky showing between them. Another boreal winter bird, the American Gos-
hawk, in adult plumage, wears a beautiful combination of the color of bare
twigs and deeply shadowed snow; and the nuthatches also have the same snow-
shadow color on their backs.

Among the Fringillide, the best example of a white-marked northern bird
is the Snow Bunting (Passerina nivalis), common to both continents. Some
of the redpoll linnets (Acanthis) have much white in their make-up (though
mixed and blended rather than in clean spots). Some of the crossbills, and
the pine grosbeaks, also have a share of it. But with most of the northern
conivorous and bud-eating jringilline birds, red plays an important part, in
the winter as well as in the summer plumage. For what are the chief colors
of field and forest landscape in the northern winter? Three of them, black
and white and blue, have already been named; what are the others? Soft
red, gray (of tree trunks), and dusky green. Vinous ash-color ranging fairly
into red is the hue of one large and ubiquitous element of these winter scenes,
namely, the outer twigs of all the deciduous trees and bushes, covered with

116

buds. (See Plate VI again.) Except when a wet snowstorm or an icestorm
has plastered and veiled these twigs, the average northern landscape in win-
ter is full of great masses of soft, purplish red, reaching here and there a
brighter tint. Golden brown, varying to red and purple, is also the color of
the cones of spruce and pine and fir trees. It is among these pink and bronzy
twigs and buds, seed tassels and cones, that the northern grosbeaks, linnets,
and crossbills get their food, and the red or reddish colors worn by many of
them are therefore in full accord with their environment. So it is also that
the red spots on the heads of the males of northern woodpeckers are not dis-
cordant notes in their obliterative pattern.

Female crossbills and pine grosbeaks are olive-green, olive-yellow and
gray—the colors of tree trunks and the foliage of evergreen conifers, and
many of the cones themselves.

The coloration of some of these birds, notably the Red Crossbills, some-
times helps to produce a truly mimetic effect. In conformity with their acro-
batic habits of topsy-turvy climbing and feeding, these crossbills have a very
scant obliterative shading. In a full, unbroken light their solidity is therefore
apt to show, and when they sit or cling on coniferous trees they often look
much like cones, by virtue of their similar colors and not dissimilar shape.

Once more we must return to the subject of obliterative white markings
on birds’ upper sides. The birds that wear them may be grouped as follows:
those that live high enough up in trees or bushes so that glints of sky and
gleaming foliage-vistas are common factors of their background; those that
live on the water or the borders of water, where reflected glints of sky are com-
mon; and, last but not least, those which live amid snow. Predatory birds
that are mainly white all over, like many sea birds and the Snowy Owl, are,
as we have shown, equipped for the greatest possible elusiveness when seen
against the luminous sky by animals beneath them. The application of this
principle among mammals we shall describe in a later chapter. Its bearing
on the coloration of birds alone is large, far larger than one would at first
suppose. It is involved, for instance, in such cases as those of the snow-

117

white herons, egrets and swans, whose whiteness tends to efface them against
the sky, in the view of their aquatic prey and enemies, as no other color or sys-
tem of colors could. Outside of the several classes above named, which
means among ground birds and birds of the interior forest gloom, white mark-
ings are practically wanting, with the exception of those that belong purely
and simply to obliterative shading, and the occasional white tail-spots, dis-
played chiefly in flight, which we shall consider in a later chapter.

The foregoing nineteen chapters together form an exposition, however
fragmentary, of all the main laws of disguising-coloration as applied to birds,
in as far as they have yet been discerned by my father. In truth, although
we have disclosed much that is new, even in addition to the big general prin-
ciples of obliterative shading and picture-patiern, yet the subject is no more
than broached.

For several reasons we have seen fit to treat of birds in more detail than
we shall attempt with other classes of animals. In the first place, birds: are
ahead of all other classes, with the doubtful exceptions of fishes and lepidop-
terous insects, in the elaborate variety and extreme development of their dis-
guising-coloration. (The slender, simple hairs of mammals, for instance, are
but a paltry medium for the building up of patterns, relative to the broad, flat
and subtile feathers with which birds are covered.) In the second place we,
personally, know more about birds than about any other animals. In the
third and last place, the main principles of disguising-coloration are the same
throughout the animal kingdom, and therefore if one describes them some-
what minutely in connection with one representative class, the other classes
can be dismissed a great deal more briefly.

The next three chapters will deal with mammals.

118

PLATE Vil

ANOEN BecO.aint

EXPLANATION OF PLATE VII

- COTTONTAIL RABBIT.

Painted by .Gerald H. Thayer. Background mainly by Emma B. Thayer and A. H, Thayer

CHAPTER XX

MAMMALS. GENERAL PRINCIPLES OF THEIR DISGUISING-COLORATION. FULL
OBLITERATIVE SHADING ALMOST UNIVERSAL AMONG THEM. EXCEPTIONS
CONSIDERED

LMOST all mammals, from some of the biggest oceanic cetaceans to
the smallest terrestrial quadrupeds, are equipped with a full obliterative
shading of surface-colors. That is, they are darkest on the back and lightest
on the belly, usually with connecting intermediate shades. White is by far
the commonest color for the middles of their undersides, while the dark of
the upper sides very often culminates in a black or dusky median line, a sort
of painted ‘ridge pole,’ laid along the center of the back, over the tips of the
dorsal vertebree. With or without such extreme accentuation, complete ob-
literative shading characterizes most of the species of almost all the mam-
malian orders. This generalization applies to the great order Marsupialia,
comprising the kangaroos, opossums, phalangers, the Tasmanian wolf, and
many other forms; to the marine order Cetacea (whales, dolphins, porpoises,
etc.); to the order Chiroptera, or bats; to the vast order Rodentia, including
rats, mice, squirrels, beavers, hares, agoutis, porcupines, etc.; to the order
Insectivora (hedgehogs, shrews, moles, etc.); to the order Ungulata (hoofed
animals, among which we may here include, for convenience, the elephants
and the hyrax, as well as the tapirs, rhinoceroses, and the hippopotami); to
the great order Carnivora (containing the cats, from the lion to the lynx, the
civets, mongooses, and hyenas; the canine beasts—dogs, wolves, jackals,
foxes, etc.; the otters, weasels, raccoons, badgers, bears; the sea lions, wal-
ruses and seals); and to the order Primates, including lemurs, monkeys, apes
and man. But in all the above-named orders, and notably in Ungulata, Chir-
optera, and Primates, there are exceptions to the rule. These exceptions are

119

most significant, since, in almost every case, they accompany some important
peculiarity in the animal’s habits or physical characteristics. In the cos-
tumes of many bats, for instance, the counter shading is defective, or alto-
gether lacking, the fur of the lower surface being almost or quite as dark as
that of the upper. But this is in strictest keeping with their habits, for they
are nocturnal and volant, flying swiftly, and for the most part feeding on the
wing, like goatsuckers, while, unlike goatsuckers, they sleep by day in the
pitchy darkness of deep caves and ruins, or in hollow trees, suspended by their
hind claws, and hanging head downward, perpendicularly. Hence, it ap-
pears, Nature has been very little concerned with giving them disguising
coloration. Their perpendicular sleeping-posture in itself precludes the pos-
sibility of their benefiting by the regulation obliterative shading while they
are at rest. If they are to be counter shaded at all, it must be from tail to
head, rather than from back to belly. Traces of such an aberrant shading
exist on many species, in the shape of white or yellowish markings on the
face,* and a brown paler than that of the rump and belly on the fore-back
and fore-breast. This partial counter shading, as well as bats’ prevailing
earthy and rock-brown color, serves them in the cases where their roosts are
more or less exposed to the daylight. Some kinds, indeed, habitually roost
in the open air, under big tropical leaves, under the branches of trees, and
on their trunks. The tree-trunk species while roosting are lighted as are
scansorial birds, and for obliteration they would have to be counter shaded
in the normal way,—as some of them are. But several of these open-air bats
are developed for mimicry instead of obliteration. Thus a beautiful little
South American species is formed, marked and colored to look like a woody
knot or other excrescence on the underside of a mangrove branch, whereto it
clings, by day ; not hanging downward, but pressed close against the bark,
holding on both with feet and finger-hooks. Usually several are found to-
gether, in a neatly distributed little group. Disturbed, they take wing all
together, with a tiny, complaining twitter, and fly away like a troop of sand-
* See also Chapter XXII, p. 157.
I20

pipers; alighting again, daintily and quickly, on the first new branch that
suits them,—or sometimes wheeling and returning to their former perch,—and
instantly they are changed back into lifeless knots.

When a normal obliterative shading does exist on bats, as is the case with
a good many species, its main service is probably the making them addition-
ally elusive in their crepuscular and nocturnal flights. The shading is usually
rather slight, from deep brown to paler grayish, but it sometimes reaches
dingy or even pure white.

There is no other important order of mammals in which obliterative shad-
ing and disguising coloration in general play so small a part. The compara-
tively few other beasts whose costumes are notable for their nonconformity
with the predominant rules of obliterative coloration, may be grouped as fol-
lows: They are either strictly nocturnal (some of the smaller carnivora, and also
some beasts which are large and fearless, but only semi-predaceous, e. g., many
bears), or fossorial, living almost wholly underground (some edentates and
moles), or arboreal, skulking (wont to take refuge in thick coverts and dense
shade), and also acrobatic, often standing erect, and thus exposing their un-
dersides to full light (e. g., some of the apes and monkeys), or protected by
some extraordinary defensive equipment, so that they are in little or no dan-
ger from the attacks of predatory creatures (e. g., hedgehogs, porcupines,
echidnas, pangolins, and some armadillos), or they enjoy a like security by
virtue of their gigantic bigness, and, being herbivorous, have no need of ob-
literative coloration to aid them in securing their food (e. g., elephants, rhi-
noceroses, and hippopotami). Compared with the vast roll of the species
equipped with full obliterative shading, the exceptions contained in these five
classes are numerically insignificant. But they are important as bearing
further weighty witness to the beautiful completeness of the correlation be-
tween animals’ modes of life, defensive and offensive armaments, and dis-
guising-coloration. The hedgehogs, porcupines, and echidnas (belonging
respectively, in the sequence named, to the orders Insectivora and Rodentia
and the order Monotremata of the strange subclass Ornithodelphia) are all

I21I

equipped with a thick coat of formidable spines, but have no obliterative
‘shading, nor any other pronounced elements of concealing-coloration; whereas
their closest relatives which lack the peculiar defensive armaments are all
(if we set aside a few fossorial forms) obliteratively colored to the full. The
echidna’s sole known ally, Ornithorhynchus paradoxus, the Duck-billed Plat-
ypus, has no spiny mantle, but its brown furry covering is obliteratively shaded.
So also with the coypou, beaver, and other rodents more or less closely allied
to porcupines, and with all the spineless Jmsectivora akin to hedgehogs, with
‘the possible exception of a few of those which live in dark tunnels under-
ground, namely, moles'and shrews. But the most strictly fossorial shrews,
and even moles, must sometimes come out into the daylight, where they are
exposed to the attacks of predaceous birds and beasts; and accordingly we
find some degree of obliterative shading in the coats of almost all the species.
There may be some kinds which are as dark on the belly as on the back; but
not one of the most monochrome-looking species we have examined has proved
to be so.

Among apes and monkeys, the want of pronounced counter shading is by
no Means uncommon, though it does not characterize the majority of speciés.
This lack may be fully seen on the big anthropoid, semi-erect apes, the scrawny
hair of whose breasts and bellies is as dark as that of their backs. But,
thanks to their size and strength and ferocity, these great apes belong in part
to the class of ‘immune’ beasts, while they also lack the need of obliterative
coloration for offense which the truly rapacious animals have. The Orang-
outan of Borneo is described as being the king of its native jungles, dreading
only man; and we may well assume that the huge gorilla of central Africa
enjoys equal privileges.

It might be supposed that whales were sufficiently protected by their
colossal size and strength, and that the toothless kinds, which feed on
the minute, lowly animal organisms that swarm in the ocean like dust
motes in-house air, would have no possible need of any kind of disguising-
coloration. Yet almost all of them have a fully developed obliterative shad-

I22

ing,* and almost all are subject to dangerous and deadly attacks from smaller
marine animals,—such for instance as the Grampus or Killer (Orca gladiator).

Sea-cows or manatees, and dugongs (order Sirenia), those uncouth sur-
vivors of an ancient race of littoral-marine and fluviatile herbivorous mam-
mals, are not pronouncedly equipped with obliterative shading. They are
colored like grayish mud and dingy water, however, and tend to be palest
underneath.

The predatory and semi-predatory land beasts which nearly or quite lack
obliterative shading are few in number, and, as has been said, they are chiefly
nocturnal.t Almost all belong to the group Arctoidea, or bearlike animals.
Good examples are the black and brown bears of Europe and America, the
Polar Bears (Ursus maritimus) the Wolverine (Gulo luscus), and several ex-
clusively American beasts, the skunks (Mephitis and Conepatus), and the
Fisher or Pennant’s Martin (Mustela pennanti). But, though largely without
counter shading, some of these animals are obliteratively colored to a high de-
gree. The Polar Bear, like the boreal foxes, hares, weasels and ptarmigans
in their winter dress, is immaculate white, above and below; and, as has been
explained in connection with ptarmigans (Chapter VII), this uniform white-
ness is about the nearest approach to perfect obliterative coloration that an
inhabitant of realms of glaring snow and ice can have, because there the
monotonous, perfect whiteness makes counter shading inadmissible, since
it would involve making the beast’s top darker than the surrounding
scene.{ The shadowed and therefore too dark underside cannot be light-
ened, but neither must the fitly illuminated white back be darkened to
match it, for then there would be a monochrome, complete (although flat-
seeming) beast-form to silhouette against the background. The skunks,
and in less degree the wolverine, are equipped with wonderfully efficient

* Those whales which prey, more or less, on forms that have both sight and power of locomotion,
must be quite as much helped by obliterative coloration in their approach to such prey, as any of the
beautifully counter shaded fishes that hunt in the same waters.—A. H. T.

: + The slight counter shading of black nocturnal animals has apparently the exact degree to defeat
the very small illumination of night—A. H. T. t See also p. 151.

13%

ruptive patterns, of a peculiar sort, whose function will be explained in a
later chapter. The other animals above named—brown and black bears
and Pennant’s Martin—are all nocturnal. The bears, furthermore, are too
big and powerful to need defensive coloration; though, being partially rapa-
cious, they do not wholly lack disguising-patterns. (See Chapter XXII.)
Thus only the cases of the Fisher and a few other small carnivorous quad-
rupeds of like coloration remain in any degree anomalous, while the facts that
such beasts are nocturnal, acrobatic, and deep-forest haunting, go far toward
clearing up the difficulty.

The living members of that strange agglomeration of animals usually
grouped by naturalists in the order Edentata, are almost all nocturnal, al-
though they show otherwise great diversity of habits. Some are fossorial,
some terrestrial; others semi-arboreal; others again, arboreal; and still others
ultra-arboreal, being, alone among living mammals, practically incapable of
any mode of progression except handing themselves, belly-uppermost, along
the undersides of tree-boughs and vines. Of course I refer now to the sloths,
Bradypodide. ‘Their protective coloration is probably. mimetic, in part at
least, like that of certain bats, already mentioned. To be sure, they are often
equipped with a slight inverted counter shading (from darker bellies to lighter
backs, as in the case of many of the lepidopterous larve which feed and rest
upside down); and their coloration often inclines also toward the ‘ruptive,’
based on bold, arbitrary patchiness. But these equipments are irregular
and inconstant, and rarely or never would they appear to be of dominant im-
portance. On the other hand, many travelers have commented on the mimetic
function of sloths’ queer, weedy-furred coats, aided by their shapelessness and
sluggish habits; and such is very probably their chief protection. Hanging,
lumplike, up among the complex, tangled forms of branch and leaf and vine
and vegetable parasite, their rotundity perhaps revealed by the insufficiency
of their counter shading, and at the same time obscured by their irregular,
shaggy coats, they may well be hard to detect as animate forms. For they
must look very much like masses of moss, withered air-plants, or other vegetable

124

débris, or like parts of moss-draped or ragged-barked boughs or trunks. So
travelers have said, and in this case there seems to be no reason to question
their interpretation. Sloths vary widely in color, but a rich olive-brown is
perhaps the most characteristic tint. Sometimes they are almost green, owing
to a growth of minute alge on their fur; and this of course enhances the mimetic
effect, allying them in the very ingredients of their superficial structure to the
vegetable masses all about them. Again, they are sometimes rather brightly
varied with patches of dark brown, blackish, dull orange and yellow, and even
white; but these markings barely attain the rank of true ‘ruptive’ patterns.
One marking, however, to which they are very prone, is extremely interesting
and noteworthy. This is the blackish stripe or spot on the fore-back, sur-
rounded by a rim of light color, varying from orange brown to white. Strangely
enough, this marking is almost precisely duplicated on the head of a species
of sphinx-moth larva (see Plate XV, Fig. T, Chapter XXV) and it there plays
an important and unmistakable part in the imitation, beautifully achieved by
the aspect of the entire caterpillar, of a pendant, curled-up, brown dead leaf.
The larva hangs head downward, and its white-rimmed black spot pictures
the shadowed hole at the tip of the pendant leaf-roll. There seems very little
room for doubt that a like effect is achieved by the peculiar shoulder-spot of
the sloth. Evidently, this simulates a shadowed orifice, with brightly con-
trasting outward rim, in the bottom of the vegetable mass mimicked by the
entire beast. (See also page 157 of Chapter XXII, and Fig. 120.)

The armadillos (Dasypodide), another family of edentates, are terrestrial
and fossorial, and almost hairless. But they are partially protected from
their enemies by a hard, annulated shell, as well as by their prodigious dig-
ging-powers. Some species roll up into almost invulnerable balls, as do
their African and Asiatic relatives, the armor-scaled pangolins (Manide).
Both these families, besides being chiefly nocturnal, belong perhaps to the
group of specially protected animals (although their armament is purely and
passively defensive, like that of tortoises, and unlike that of porcupines), and
their protective coloration accordingly is meager and irregular. Armadillos

125

are earth- and sand-colored above, and their broad, shelly roof, somewhat
counter shaded, extends so far down over the sides as almost wholly to hide
the shieldless and more or. less hairy under parts, which, in conformity with
the common law, are often decidedly paler in color. It is doubtful, though,
whether the ventral paleness has in this case much significance beyond the lax
and aborted pigmentation of a surface almost never exposed to view. But
armadillos’ heads and tails are always (?) counter shaded.

The Myrmecophagide, or American Ant-eaters, are all fully furred, and,
despite their nocturnal habits, obliteratively colored. Only three species are
known, namely, the Great Ant-eater (Myrmecophaga jubata), the middle-
sized Tamandua (Tamandua ietradactyla), and the Little Ant-eater (Cyclo-
thurus didactylus). M~yrmecophaga is strictly terrestrial, but does not burrow;
Tamandua is chiefly arboreal, and Cyclothurus strictly so, being halfway to
the sloths in habits and demeanor. The two larger kinds lack diurnal ob-
literative shading, but are equipped with powerful ruptive patterns of black,
white and gray.* The exquisite, pale-brown furry coat of the little Cyclo-
thurus bears a rather faint obliterative shading, and a blackish ‘secant’ stripe
along the underside.

The ‘‘Aard-vark”’ of South Africa (family Orycteropodide) represents the
only other type of edentate that remains to be considered. It is strictly noc-
turnal, fossorial (living in deep burrows), and extremely timid and wary. Its
body is scantily clothed with coarse brownish hair, and has in all probability
the regular slight ‘nocturnal’ counter shading. (See the second footnote on
page 123.)

I have already named the general rules which seem to govern these va-
rious breaks in the prevalence of full-blown obliterative coloration among
mammals. To recapitulate, the exceptions occur, in the first place, among
beasts that are habitually or very frequently hidden away from the light,
either underground, in caves or hollow trees, in thick vegetation, or in the
cloak of night. In the second place, they occur among beasts, mostly non-

* See Chapter XXII, p. 149.
126

predaceous, which are almost or quite immune from danger at the hands of
their wild fellow-creatures, by virtue either of their great size and strength,
or of a potent fixed defensive armament. In the third and last place, a few
defenseless arboreal mammals are equipped for mimicry rather than oblit-
eration.

It is, then, among unarmed, daylight-inhabiting mammals, and among
the purely rapacious mammals, both of the plains and of the forest, that ob-
literative coloration, based on full and simple obliterative shading, reaches
its highest and most uniform development. Many of the terrestrial beasts,
particularly those of the open country, are equipped with full counter shading
and ‘ground’-color alone, almost or quite without markings. Such are lions,
wolves, jackals, kangaroos, hares and rabbits; marmots, some gophers, and
several smaller rodents and marsupials; as well as many of the big ungulates
or ruminants, such as wild asses, some wild bovines, and many deer and
antelopes. It has long been known that the animals of the desert are ex-
tremely alike in coloration—insects, reptiles, birds and mammals all sharing
the same sandy brown. But codrdinate with this fact is one hitherto ignored,
‘namely, that the colors of these desert animals do as universally and unvary-
ingly constitute a perfect obliterative gradation of shades, from dark above
to light below. As there is great monotony and uniformity in the animals’
lighting and backgrounds, so is there sameness in their color-tints, in their
all-essential obliterative shading, and in their scanty pattern,—when patterns
occur, for they are often wholly wanting. Among the simply-colored mam-
mals named above, the lion and the jackal may fairly be said to belong to the
desert class. Most of the others are more characteristically inhabitants of
grassy prairies; while some are partially sylvan. The Cottontail Rabbit
(Lepus floridanus transitionalis) shown in Plate VII, at the head of this chap-
ter, is a fair type of the fully counter-shaded, plain-colored terrestrial mam-
mals.* ‘These paintings of ours (rabbit, Ruffed Grouse, Copperhead Snake,

* More strictly, however, this hare is a semi-patterned, semi-sylvan beast, and one in whose
normal backgrounds there is a good deal of variation.

T2327

caterpillars, etc.) are, we believe, the first ever published which rightly illus-
trate and in some respects do justice to the wonderful effects of obliterative
coloration, based on the great law of obliterative shading. Many photographs
of wild animals in nature (e. g., the ptarmigan shown in Fig. 41) illustrate
the same thing with compelling force and beauty. Photography, indeed, is
the great ally of those who would expound the laws of obliterative coloration;
and it is destined—more swiftly now that the underlying principles of that
beautiful phenomenon have been disclosed and analyzed—to effect a funda-
mental change in men’s knowledge of the looks of animals in nature; and, by
the same token, in the drawings and paintings men make of these wild ani-
mals. The world has had enough, or must soon have had enough, of pic-
tures of birds and beasts with their light-and-shade falsified to make them
show. Outdoor nature as it really is, in the matter of the marvelous and
exquisite visual correlations between animal and environment, offers to art,
in this late age, an almost boundless virgin field.

Figs. 84-89 and 93-04 are all photographs from live mammals, either in
nature or captivity. Fig. 86 shows a tame hare upside down against a nor-
mal background. (See also the photographed flat hides of mammals shown
in Figs. 11, 12, and. 13 of Chapter II.)

Mammals, totally unlike birds, butterflies, and even fishes and reptiles,
are almost wholly devoid of really gaudy surface-colors. In some few cases,
mammalian fur reaches or nearly reaches the standard of pure color in the
direction of yellow, green, and possibly orange; but its normal and usual range
of tint is through all the grades of neutral, from black to white, and through
the entire scale of browns and grays, from vivid rust-color to cold bluish
gray. When clear, gaudy color does occur on mammals, it is usually in the
naked skin, as on the faces and rumps of certain monkeys and baboons.
Now whether, as may well be the case, mammalian hairs are, as compared with
the feathers of birds, the scales of butterflies, and the skin and scales of fishes,
structurally incapable of producing brilliant colors, there is yet a sufficient

ulterior reason why we should expect to find mammals brown and gray,
128

Fig. 84. Wild
Cottontail Rabbit
(Lepus floridanus
transitionalis) in po-
sition. ‘Obliter-
ated’ by counter-
shading and faint
ground -picturing
pattern,

Photographed from
life, outdoors. Captive
rabbit.

Fic. 85. Domestic
hare.’ Obliterative
shading, etc.

Photographed from life.

Fic. 86. Domestic
hare laid on its back,
outdoors, so that the
obliterative shading
is reversed.

Photographed from life.

or at least much less brightly colored than birds, etc. The fact that they
are so becomes in fact one more strong link in the chain of evidence in proof
of the universal and paramount importance of concealing-coloration. Mam-
mals (we will exclude the aberrant forms, as the bats—winged, nocturnal,
and cavern-haunting—and the marine types) are characteristically flightless,
and hence, in a great measure, tied to earth. In the forest, the outermost
skyward excursions of the most arboreal species rarely or never take them
into the gay regions inhabited by the more brilliant birds and butterflies.
For these are masters of that unstable element, the air, and can go whither
they please above as well as upon and through the ground and the forest.
Hovering, flitting, perching lightly, always ready to resort to their wings in
an instant if the perch should fail them, even many of the heavier members
of this gifted class—even many of the birds, in short—are wont to pass most
of their time in the brilliantly lighted outermost border of the forest, among
the very tips of the slenderest twigs, where most of the fruits and flowers grow,
but whither even the most agile climbers of all the wingless mammals dare
not venture. Metaphorically speaking, birds and butterflies are creatures of
the grave and ponderous globe’s exterior efflorescence, of the colored foam
at the outermost edge of things, of the borderland between earth and sky;
while mammals, man included, are citizens of the sober underworld. Plod-
ding, earth-bound things, they walk upon the solid ground, and drive their
tunnels in the darkness under it; while some of them ascend its skyward ex-
crescences, the trees; but high as they may go they are still the creatures of
the ‘underworld,’ and the bright realm of butterflies and birds is still as a
rule above them. By their life-laws, they are forever associated in close con-
tiguity with things brown and gray and black;—mud, sand, the dead leaves.
and twigs of the forest floor, rocks and pebbles, tree trunks and branches—
and the black holes and shadows among all these things. Some few of the
most arboreal kinds live in the realm of preponderant sylvan greenness (see
p. 108 of Chapter XIX), and several of these (small monkeys, etc.) have olive-
green or even clear green and sometimes yellow fur. But as no wingless

129

mammals attain, except in rare chance moments, to the bright and efflores-
cent ‘borderland,’ the headquarters of the brilliant butterflies and_ birds,
so are there practically no really gaudy mammals. Furthermore, it will be
found, in almost every case, that the birds most closely akin, in’ways of life
and local habitat, to some dull-colored mammal, are themselves dull-colored;
for birds are distributed ubiquitously, from their own special realm to the
mammals’ stronghold, the solid ground below. (See p. 107 of Chapter:
XIX.) Even outside the forest, the characteristic difference between the two
classes, in habits and in accompanying coloration, is maintained. Wherever
there is vegetation of any sort, down to lowly herbage, there it is the general
wont of birds to feed and fly and climb on #op of it, in the light, and amid
bright colors, and the general wont of mammals to feed and crawl about
below it, amid shadows and dull colors. This generalization applies even to
semi-aquatic birds and beasts. Wood Ducks swim high, and often sit on
trees; kingfishers sit on stumps and branches above the water; Purple Gal-
linules walk about, erect, on lily pads; and all these birds are marked with
rich or brilliant water-colors. Otters, muskrats, beavers, capybaras, and
other semi-aquatic mammals, swim either under water or almost submerged,
showing only a low line of back and head. When they are out of the water
they are always close to terra firma—on the muddy shores, in holes, or run-
ning about under the bushes and weeds and tree-roots; and no one of these
beasts is brightly colored. But here again we find that the bird tribe invades
the mammal tribe’s proper realm, and shares its system of dingy colors,
though the mammal tribe cannot reciprocate. Thus there are rails and other
marsh birds that live like skulking quadrupeds, on the ground below the reeds
and bushes, and like them also they lack brilliant colors.* To sum up: on
the bare fields and deserts, in the dusky forest shades, and below the taller
vegetation in the marshes, there are ‘mammal-colored’ birds; but nowhere
are there ‘bird-colored’ mammals. (A statement essentially correct, though
for absolute accuracy it would need some qualifying.)

* Except on their beaks, legs, etc., in the breeding season.

130

Equally in keeping with mammals’ lack of gay colors and minutely elab-
orate patterns is the fact that the great majority of them are nocturnal, hiding
by day in hollow trees and holes in the ground. Nevertheless, in addition to
a complete general adequacy, based, for the most part, on full and perfect
counter shading, mammalian concealing-costume presents many beautiful
types of generalized obliterative picture-pattern. Some of these are the sub-
jects of our next two chapters.

131

CHAPTER XXI

MAMMALS, CONTINUED. MARKINGS OF COUNTER-SHADED MAMMALS. THE
MAIN TYPES OF THEIR OBLITERATIVE PICTURE PATTERNS

HILE the beasts of the open land, such as lions, kangaroos, and many

hares, are notable for their almost complete lack of markings, al-

though obliteratively shaded and tinted to a high degree, the costumes of many
of the forest-haunting and tree-climbing mammals are characterized by strong
and beautiful picture-patterns. Among these, there is perhaps none more
potent and remarkable than the checkered sun-fleck and leaf-shadow pat-
tern, worn by leopards, jaguars, ocelots, giraffes, and other sylvan mammals,
and even by some snakes—e. g., several of the great constrictors. It varies, of
course, from species to species; but its essential character is always the same,
and it is always the handmaid of complete obliterative shading. Who has
not noticed, in the forest, the flickering play of circular (or broken) sun-flecks
and branched, encompassing leaf shadows? There is no more typical and
familiar sylvan sight. Where the forest’s crown is not too dense, this beau-
tiful tremulous pattern marks all the brown ground where the matted dead
leaves lie, and even checkers the sides and bases of some of the upright trunks,
and the tops and sides of the naked lower branches. In deeper woods, where
the leafage is extremely full and crowded, little or none of this sun-engendered
pattern penetrates to the ground, which then is cloaked in uniform and quiet
shade. But somewhere between the dim brown ground and the green and
gaudy-flashing tree-tops there is always a large intermediate tract, where,
amid trunks and spreading branches, twigs and scattered leaves, the check-
ered pattern reigns supreme, dancing softly on the upper side of everything;
and, helped by the varied glinting of the lower leaves themselves, it transmutes

132

Fic. 87. CHap. XXI. ag ge of acaptive Jaguar, with a background, as of torest leaves in light and shadow, painted around him.

The Jaguar is the same as that published by C. W. Beebe in his “The Bird,” and is here used with the kind permission of Mr. Beebe, E. R. Sanborn and Henry Holt & Co.

all that portion of the forest into a shimmering disorder of small, shattered
lights and shadows, in which the actual solid details seem inextricably merged.
To witness this effect in full, one must of course look at the scene from a
point somewhat above it; but the pattern one sees in looking upward through
the forest leaves, where they are not so crowded as quite to hide the sky, is
of much the same nature. Indeed, this latter sort is in some respects more
like that worn by leopards, etc., than is the true sun-fleck pattern. For the
predominant effect of the leopard’s pattern, and of that made by leaves against
the sky, is of symmetrical dark marks on an irregular light ground—propor-
tions which the sun-fleck pattern inverts, except where it is exceedingly pro-
fuse. But what we see on the hides of these checkered sylvan beasts is really
an apt and efficient generalization of this entire class of forest-patterns, includ-
ing the much-used picturing of holes, done all in brown and black and golden
forest-interior color.

Among the species named at the beginning of this chapter, all but the
giraffe are arboreal—that is, tree-climbing—while the giraffe’s great height
keeps him also in the region of frequent sun-flecks, as he feeds among low
trees and lofty bushes. But the ‘checkered’ pattern in general is so charac-
teristic of all lights and shadows in the woods, that, whether the beast so marked
have for a background the variegated middles of trees, an under view of their
leafy tops against the sky, or the flat brown forest floor, he will almost al-
ways be adequately ‘obliterated.’ Everywhere, under leajy trees, exist these
simple, elemental patterns, whose likeness on the hides of beasts men deem
so beautiful.

A leopard or a jaguar stretched out on a lofty branch, lying in wait for
monkeys, his deceitfully counter-shaded and spotted coat dappled into still
further indistinctness by the very shadows and sun-spots it counterfeits,
must be about the most insidiously inconspicuous of hunters. (See Fig. 87.)
But not all leopards and jaguars have this brilliantly obliterative forest-color-
ation. Both species are rather prone to melanism, being sometimes almost
wholly black, with scant traces either of counter shading or pattern. It would

133

be very interesting to discover whether or not the dusky individuals tend to
be more strictly nocturnal in their habits; for they are certainly less well
equipped for stalking and ambushing their prey in the broad daylight.

The giraffe’s or camelopard’s pattern is simpler than the leopard’s, con-
sisting of but two well-marked cclor tones instead of three. The dark spots
are rich brown instead of black, representing, as it were, a consolidation of
the leopard’s two darker tones. Giraffes, however, are subject to a good
deal of individual (?), sexual, and geographical variation in the color and
shade of the spots, as well as of the branching, irregular light bands by which
the spots are divided. But their pattern always maintains its potency for
obliteration, particularly in (low) woods, amid shimmering sunshine and
leaf shadows, and more distant leaves and leaf-clusters and small branches
silhouetting against the sky. In this, their foremost and special obliterative
function, the mammalian and reptilian checker-patterns, codperant with a
full obliterative shading, must be reckoned among patterns which picture the
background, like those much more elaborate and minute of many birds.
(See Chapters IV, V, VI, VII, etc.) But they have also, in common with
almost all other patterns, and notably all that are sharp and bold, a simple,
inherent obliterative effect. The sharp spots thickly scattered over the leop-
ard’s coat, and the eccentric patchwork-marks worn by his huge, stilt-legged,
ruminant namesake, are in themselves a kind of mask or veil for the solid
animal forms beneath them. ‘Their bright, irregular and inorganic pattern
takes from the visibility of their wearers’ contours, and goes far toward effac-
ing all the minor details and chance-shown lesser lights and shadows of the
beasts’ solid but obliteratively shaded forms. A glance at Figs. 1, 14, and
87 will tell the reader more about this than many words. In the case of such
an animal as the Jaguar shown in Fig. 87, the perfection of the obliterative
shading, denying as it does the presence of a solid body underneath the spots,
tends to make these seem to belong to the background, even if that is not
elsewhere spotted; and thus the simple ‘retrocessive’ obliteration is in part
maintained. Nevertheless, a highly spotted (or otherwise closely marked)

134

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animal, even though perfectly counter shaded, is of course out of place and
more or less clearly visible against a perfectly plain background, because his
figure silhouettes against the monochrome scene by virtue of its continuous
pattern. This fact, or the converse of it, the noticeableness of a monochrome
object against a patterned background, has already been demonstrated (Chap-
ter III, Figs. 15-16). But few natural backgrounds, even in the open lands,
are entirely immaculate; and hence some degree of flecking is nearly always
advantageous, though often not essential, in an animal’s obliterative colora-
tion.

There is a complete gradation of types between the leopards, ocelots,
giraffes and boas, with their rich, specialized, forest-picturing ‘checker’
patterns, through such more weakly and ambiguously spotted beasts as the
Ounce and Serval—the one apparently modified for snow and the other for the
more open country—to the immaculate lions and (certain) antelopes. In
the same way another beautiful and important type of obliterative pattern,
namely, transverse striping, grades from its extreme development on the
zebras and tigers, through various lessened and modified forms, to its last
and slightest appearance on such animals as Livingstone’s Eland, and other
antelopes, from which it is but -a step to the stripeless ruminants and car-
nivores of the open ground. Among all the bolder obliterative patterns worn
by mammals, that of the zebras (Equus zebra and E. burchelli) probably bears
away the palm for potency and beauty.* The wonderful photographs of
live wild zebras (Figs. 88 and 89), here reproduced with the permission of
their author, Herr Schillings, and his publishers, clearly illustrate one main
phase of the obliterative force of these beasts’ patterns. The brilliant cross-
bands ‘cut their wearers all to pieces,’ and look exactly like the stripings of
the lighted reeds across their. shadowed background. To aid in a fuller

* Kipling, in one of his “‘ Just So Stories,” ‘‘How the Leopard Got His Spots,” which we have
just read for the first time, gives a most keen and appreciative description of the marvelous conceal-
ing-power of the costumes of the zebra, leopard, and giraffe. He does not analyze the magic of these
patterns, for he says nothing of the principle which underprops it, counter shading; but the magic in
operation he has perceived and told about as no other man we know of has.

135

analysis of this effect, and kindred ones, we give also some diagrams—some
imitation zebra pictures. Figs. 90, 91, and g2 are photographs of a zebra-
shaped model cut out of flat cardboard, and placed amid straws and imita-
tion reeds or grasses, artificially arranged. In Fig. go the grasses relieve
light against a dark background (as in the real zebra photographs by Schill-
ings), and the zebra-to-be—now a wild ass (!)—is tinted uniformly with a shade
intermediate between background and grasses. Being actually flat, as the
real live zebra is made to appear by its full obliterative shading, this mono-
chrome model is not revealed by any look of solidity; yet it is visible and rec-
ognizable, because its stripeless surface, with its organic and peculiar outline,
interrupts and relieves against the striped pattern behind it. In Fig. g1, the
same model, against the same background, has been converted into a zebra,
by the application of the proper bands or stripes,—and notice the result! The
cardboard figure, standing almost where it stood before, and in exactly the
same lighting, has practically disappeared from view. Its sharp bands carry
the striate pattern of straws and dusky background across its every part,
thereby obliterating it almost completely. (Schillings’s zebras didn’t hap-
pen to have a fully and evenly striped background at the moment when he
photographed them,* and therefore the effect of actual background-matching
is only fragmentarily shown by his pictures.) Fig. 92 shows the same thing
over again, with the difference that the striped background is made by imi-
tation reeds relieving dark against white paper; the reverse of the former case.
These two sorts of background are almost equally well suited to the zebra-
pattern, as our pictures show. Both are imitated from nature, the one cor-
responding to a landscape with brightly lighted grasses, reeds, or other tall
and slender plants, relieving against dark ground or water, or against the
shadowed interior mass of their own kind (see Schillings’s pictures, Figs. 88
and 8g), and the other to a landscape in which such plants in somewhat open
array relieve darkly against bright sky or water. Again, the shadows of these
tall and linear plants—or even of plants more treelike and branching—cast
* (not to speak of the extreme abnormality of the lighting).—A. H. T.
136

Artificial ass and zebra, looked at from the low view-point of an ambushed lion, showing the effacing-effect of the stripes in
actual operation. (Study this picture from a distance.)
Substituted for the Schilling’s photograph, Fig. 89, since the book was printed.

upon the sandy or otherwise pale-colored ground in sun- or moon-light, make
a pattern very much like the zebra’s.* So also with the reflections of such
plants on quiet water. Scenes like these are doubtless typical of all the coun-
try in which zebras live. For however arid and barren, through much of the
year, are the hills and plains and plateaux over which the Mountain Zebra
ranges, or used to range, they are yet clothed with tall plants of many sorts,
including rank grasses, which no doubt stand erect for months after they are
withered by drought. Furthermore, all beasts must have water, and so the
zebras of the dry plains must needs make frequent visits to the nearest living
sloughs and rivers. There, by the water’s edge, tall reeds and grasses almost
always flourish—often in broad beds of marshy verdure—and there, where
all beasts meet to drink, is the great place of danger for the ruminants, and
all on whom the lion preys. In the open land, they can often detect their
enemy afar off, and depend on their fleetness for escape; but when they are
down in the river bed, among the reeds, he may approach unseen and leap
among them without any warning. It is probably at these drinking-places
that the zebra’s pattern is most beneficently potent. From far or near, the
watching eye of the hunter ¢ (bestial or human) is likely to see nothing, or
nothing but reed-stripes, where it might otherwise detect the contour of a
zebra. The extraordinary brilliancy of these stripes, which for the most part
are clear black and white in sharpest contrast (much dimmed, of course, by
shadows, when the beast stands amidst vegetation), makes them effectively
obliterative at a great distance, where weaker markings would merge and
vanish, thereby allowing their wearer’s contour to become apparent. Nor is
this brilliance detrimental to the effect in a near view,—the stripes, as Schill-

* One may satisfy oneself of this even in the snowy winter woods of northern Europe or America,
where, in the slanting light of sun or moon, the shadows of naked trees lie thickly scattered on the
pure-white ground. Those of the trunks are mostly parallel, and perspective gathers them into nar-
rowly banded patterns, while those of the branches, though much more irregular, also tend to form
patterns of this type.

t However largely lions and other rapacious mammals hunt by scent, it is not scent, but sight
alone, that can serve them when they are down wind of their quarry; and sight alone must guide their
ultimate killing dash and spring —A. H. T.

137

ings’s pictures testify, still play their true obliterative part, ‘cutting the beast
to pieces’ and wedding him to the strong and manifold striations of the veg-
etation all about him. Indeed, a pattern so multiplexly and fundamentally
‘secant’ ‘cuts its wearer’s aspect to pieces’ in almost every view, only fail-
ing to be purely obliterative when the beast is seen against a perjectly plain
background. Against any appropriate background, on the other hand—as
one of reeds and grasses, or even bare-limbed bushes and low trees, or sand
streaked with the shadows of any of these plants, or quiet water striped with
their reflections—its obliterative effect must be almost perfect. A slightly
different phase of this pattern’s use is that which comes into play when the
zebra stands amid lower reeds (or other plants) with its upper parts relieving
against the sky, or against dim, distant ground, or water. Its body then looks
like the upward continuation of the grasses or reeds encompassing its legs;—
the dark stripes continuing the reeds upward, and the light stripes between
them continuing the sky or other pale background downward, so that the
beast’s contour, which otherwise could scarcely fail to show in this position,
is still ‘cut up’ and concealed. This ‘letting in,’ or ‘drawing down,’ of
sky into an animal’s silhouette is a regular and frequent factor of obliterative
coloration, occurring in many forms, in many classes of animals, but most
notably among birds and mammals. The reader will hear more of it in the
next chapter.

Burchell’s Zebra, the species photographed by Schillings,* is much like
the now almost extinct Mountain Zebra in general coloration and pattern,
but its light markings are more yellowish, and the secant bands are fewer and
broader and somewhat ‘differently distributed. On the whole, the Mountain
Zebra has the more highly wrought obliterative costume, and that of Bur-
chell’s is one step down toward the much slighter pattern of the Quagga
(Equus quagga). ‘This beast, which has lately been exterminated, was banded
only on the fore part of the body, and there irregularly, with light and dark
brown. The transverse leg- and flank-bars of both zebras (but particularly

* Strictly speaking, his beasts belong to subspecifically differentiated races of burchelli.
138

Fie. 90. Cardboard ‘zebra’ without stripes, against light straws as in Fig. 91.
Photograph, retouched.

Fie. 91. Cardboard zebra among straws ‘relieving’ light, like reeds or
grasses against dark ground.

Photograph, retouched.

Fie. 93. Chipmunk (Zamias striatus) among dead leaves, its stripes
picturing sticks or leaf-edges and shadows. (These picture-patterns are, of
course, based on perfect obliterative shading.)

Photographed from life, outdoors. (Captive chipmunk.)

Fie. 92. Cardboard zebra among imitation reeds ‘relieving’ dark, as against the sky. Z
Photograph, retouched.

of the mountain kind), opposed to the more or less vertical body-bands, call
for a word of comment. They are an example of ‘secantly’ obliterative mark-
ing as distinguished from pure and simple picture-pattern. Striped up and
down, the legs would continue the body’s depiction of standing reeds or tufts
of grass, but they might also look like an animal’s legs, for their true form and
general trend would be obscured but little. The legs, like the body, must be
cut crosswise by secant stripes, if they are to be fitly disguised. As was ex-
plained in Chapter XIII, such stripes achieve their full effect only when
aided by corresponding background-markings. Though the zebra walks
amid upright grasses, etc., crisscrossing and horizontal stems and blades are
of course common enough in his haunts to yield the required amount of co-
operation to his essentially ‘secant’ horizontal leg-bands. When the zebra
is lying down, with legs outstretched, these transverse leg-bands have of
course a vertical direction, like the body-markings. ‘This, perhaps, is the
position which best favors, in the aggregate, the proper working of his ob-
literative pattern. Still another detail of these wonderful harlequins’ cos-
tumes which demands especial notice is the delicately striped head-pattern.
This is worn in almost equally high development by both zebras. It is by
every test a picture-pattern. For, just as in the case of the picture-patterned
birds (Chapter III, p. 32), this head-pattern of the zebra’s is much smaller
and finer than that of the body, as if to match a striped background decidedly
reduced by distance—just such a one as the head, being the highest part,
must normally have in relation to the lower body. Considering birds alone, a
skeptic might suggest that the smallness of the head-pattern may be merely
the simple physical consequence of the smallness of the head-jeathers; but
such a theory would break down when confronted with the fact that there is
a like proportion in the sizes of pattern between the heads and bodies of
obliteratively colored hairy mammals. A single feather often contributes
the whole of an important spot, or even several spots, to the general pattern,
so that small feathers might mean small markings; but patterns made with
hair are very different. It takes many hundred crowded hairs to make a

139

small detail of such a pattern as the zebra’s, each separate hair contributing
but a tiny share to the effect, so that the markings might be disposed quite
arbitrarily on the beast’s coat, as far as the mere form and character of their
component parts is concerned.

Near akin to the zebra-pattern is that worn by tigers. But the tiger’s
black stripes are narrower, further apart, and more broken and irregular,
while its ground-color is tawny or deep golden brown instead of white or pale
buff. The main obliterative principles, however, are alike in both. The
tiger’s coat is obliteratively shaded to minute perfection—darkest along the
ridge of the back, lightest on the throat and belly, with intermediate shades
for intermediate regions and smaller details of rotundity. His general color
is that of the interiors of bushy thickets, reed-beds, the underwood of the
loftier jungle, and all brown, half-shaded coverts; while his stripes picture
vertical stems and slender trunks in shadow, and also the sun- or moon-en-
gendered shadows that such plants cast upon the ground in opener places.
As with the zebra, however, his pattern is essentially and intrinsically ‘se-
cant’ and obliterative, and nothing short of a perfectly plain background
can neutralize its power. He is a beast who hunts his prey by stalking, often
in full daylight; accordingly, his huge form has been ‘blotted out’ by counter
shading; he is likewise a beast who hunts in and among bushy and grassy
thickets, full of upright ‘stripes’ of vegetation, and accordingly he bears a
system of generalized dusky stripes upon his brown, obliteratively-shaded
coat. The terrible inconspicuousness of the tiger in his native jungles has
long been a famous fact, and no evidence on that score need here be cited.
Suffice it to say that this inconspicuousness is due primarily to the beast’s
obliterative shading, and secondarily to his stripes and his tan-color, which
have hitherto alone been held responsible, in the opinion of men. Turn a
dead tiger or his stuffed skin upside down in a normal outdoor lighting,
and, arrange him as you will against fitting backgrounds, he will be not dim
and illusive, but conspicuous, because ,of his now inverted obliterative
shading.

140

The tiger has a vast geographical range, extending from the humid jungles
of Sumatra to the snowy mountains and plateaux of northern China and
Siberia; and like most widely distributed beasts and birds, it has developed
several regional races, differing mainly in superficial characters. As the
Ounce or Snow Leopard differs from the true leopard type in coloration,
so, to some degree, does the North Asian mountain tiger differ from the jungle
tigers of the South. Its ground-color is paler—sometimes almost ashen-white
—and the stripes are scantier and more broken. These differences correspond
to those of the beasts’ habitats—the northern tiger living amid rocks and
sometimes snow, in regions where tall upright stalks of vegetation are com-
paratively uncharacteristic features of the landscape. Thus, in almost all
cases, can one trace an apparent raison d’étre of color- and pattern-differ-
ences among nearly allied animals. There are a few cases more baffling, but
the seeming obscurity of these doubtless depends on our ignorance of many
fine points of difference or affinity in the beasts’ life histories. Some animals,
for instance, seem to have a superlatively elaborate obliterative equipment,
while other closely allied species with nearly similar habits, living in the same
regions, are patterned much more simply. This. is the case with the two
‘harlequin’ zebras and their relative the scantily half-striped Quagga. As
the Quagga was banded only on its fore quarters, so the Thylacine, or Tas-
manian Wolf, is banded only on its hind. Another Australian marsupial,
the little ant-eating Myrmecobius fasciatus, is brilliantly zebra-banded from
its shoulders to its tail, But among all the beasts that bear more fragmentary
vertically-secant patterns, the African antelopes are probably the most note-
worthy. Many antelopes of that continent, indeed, are almost or quite un-
marked—smooth brown or gray, obliteratively shaded, with the regulation
white or very pale-tinted bellies. But others are brightly, if somewhat scant-
ily, striped, and sometimes spotted, on the back and sides and legs, with white
and black—especially white. The most amply and regularly banded of these
is the Koodoo (Strepsiceros kudu), which has many vertical white stripes on a
dark-brown ground. This beast, as its markings would suggest, is an inhab-

141

itant of regions with rather ample vegetation—such as reedy river-margins.
Indeed, its average environment and its disguising coloration are very much
like the zebra’s. In the same class of ‘secantly’ striped antelopian costumes
is that of Livingstone’s Eland, mentioned a few pages back. This mag-
nificent great antelope has black marks on its fore legs, while its brown back
and sides, otherwise immaculate, are marked with five narrow vertical lines of
gleaming white, extending from the ridge of the back about two thirds of the
way to the middle line of the belly. These stripes, like those so much more
numerous and bold worn by the zebras—and even the Koodoo—are secantly
obliterative. They bring down, as it were, narrow slips of sky into the beast’s
smooth contour, when he stands upon an eminence and silhouettes against
the distance—and thus they ‘cut the contour up’ and tend to obliterate it.
Again, under other conditions, these stripes carry the aspect of stray gleaming
grasses or reed-stems upward across the eland’s earth-colored, obliteratively
shaded body. In all such views, and in others where the ‘picturing’ effect
is less pronounced, these stripes are definitely obliterative, always tending to
‘cut up’ the aspect of the eland’s form. The Common Eland wholly lacks
these markings, as do many other African antelopes; and here we have an-
other case of notable costume-differences among animals with nearly or seem-
ingly quite the same habits and environments. No doubt, however, there
are really equivalent differences in the beasts’ average surroundings, and in
their behavior, even though these have not yet been noticed by man. Thus
Livingstone’s Eland may have a greater propensity to stand still in time of
danger, or may spend more time amidst tall grasses and reeds, than those of
its near relatives that lack the secant stripes. In the same way the more pro-
fuse and variegated white markings of the Harnessed Antelopes, containing
an admixture of white spots, are probably an indication that these beasts spend
an unusually large proportion of their time in and about wet swamps and
river borders, where flecks of water-shine—glints and stripes of sky-reflection
—are common features of the scene. The small, irregularly circular white
spots on the common Harnessed Antelope are indeed almost exactly like those
142

which are prominent in the patterns of certain semi-aquatic mammals; and
they also correspond closely to the water-shine flecks of aquatic and swamp-
haunting birds. (See Chapter XI, p. 61.) Two beasts of this type are the
African Water Chevrotain (Hyomoschus aquaticus) and the South American
Lape or Paca (Celogenys paca). Though belonging to different orders (the
Chevrotain being a ruminant and the Lape a rodent) these two animals are
much alike in general habits, while in pattern they are almost identical.
The ground color of the Chevrotain’s coat is richer and redder brown than
that of the Paca’s, but it bears almost exactly the same system of white flecks
—irregular white spots, in places almost or quite confluent, and forming
longitudinal chains or stripes. If these two beasts lived in the same swamps,
naturalists would very likely consider their superficial likeness a case of ‘mim-
icry.’ But since they live on different continents, there is no disputing the
statement that they are independently equipped with water-shine patterns of
the same simple, generalized type, which occurs the world over both on mam-
mals and on birds.

As the zebras’ bands are vertically ‘secant,’ so lengthwise stripes, of which
we see the first signs on the Harnessed Antelopes and the two water-beasts
just described, are longitudinally secant, like those of certain gallinaceous
birds and sparrows, etc. (Chapter XIII, p. 78). On mammals, this truly
striped pattern appears in many forms and many degrees of elaboration, be-
ing sometimes merely secant, with no very particular suggestion of back-
ground-picturing, and sometimes highly ‘pictorial. Many of the North
American Ground Squirrels, and Spermophiles (Tamias and Spermophilus),
are marked with bright, longitudinally striate patterns of black and brown
alone. The Common Chipmunk (Tamias striatus), of eastern North Amer-
ica, has few but highly developed markings, its one composite side-stripe
being formed by a central whitish stripe inclosed within two black ones.
(See Fig. 93.) Painted thus boldly on the little beast’s obliteratively shaded,
beautifully dim and flat-looking, honey-brown body, these markings much
enhance its elusiveness by distracting the beholder’s eye from any faint mod-

143

ulations of the creature’s form which might otherwise be apparent; while each
of these stripes looks in itself like a bright stick, twig, grass-blade, leaf-edge,
or weed stem standing out above a shadow—either its own or a more general
background-shadow, which shows on either side of it. Or again, this mark-
ing suggests a shiny, cylindrical stick or stem, with its central streak of high-
light, and the bordering shadows on itself, caused by its own curvature. Still
another detail of ground-scene which these chipmunk-stripes suggest is the
pattern made by sunlight falling between parallel twigs or stems—narrow,
shadow-bordered sun-streaks on the earth or leaves or stones. They are, in
short, generalized but most efficient picture-patterns. The western Four-
striped Ground Squirrel (Tamias quadrivittatus) is colored and marked much
like the eastern Chipmunk, but its stripes, besides being more in number, are
narrower, and, as picture-patterns, perhaps even more generalized. Notable
among the several other modifications of this pattern to be found on North
American mammals is that worn by the beautiful Thirteen-lined Ground
Squirrel (Spermophilus tridecimlineatus). The black intervals between its
many light-colored secant stripes are traversed by lengthwise chains of bright
spots, like slender flower-spikes or little leaves over shadow. On some sper-
mophiles (as S. grammurus douglassit), the secant pattern is reduced to a
single broad black stripe along the middle of the back—an exaggeration of
the dusky ‘ridgepole’ mentioned at the beginning of Chapter XX.

An illustration of the obscurer type of generalized flecky background pat-
tern on mammals was given in Plate VII. It is a type extremely prevalent
among terrestrial mammals. Indeed, if we include all its offshoots, such as
the system of regular, scale-like bright flecks on a dark ground, worn for in-
stance by certain spermophiles, it is the commonest as it is the obscurest
kind of mammalian pattern. It is worn by many terrestrial rodents, etc.,
of the open ground—e. g., hares, gophers, lemmings, spermophiles—and,
variously modified, by many terrestrial forest mammals. Simplified to a
close, bark-like grizzling, it is characteristic of many arboreal beasts, such as
squirrels and some of the marmosets and lemurs. With very few exceptions,

144

patterns of this kind are accompanied by—or better, they are the accompani-
ment of—complete and perfectly efficient obliterative shading. They grade,
however, into the more bold and special types of pattern. Thus the ob-
scurely flecky pattern of some lynxes shows here and there a spot which is
halfway to the clean, sharp “rosettes” of leopards and jaguars. On the other
hand, the flecky pattern grades downward into nothing, so to speak, and
many mammals are almost or quite without markings, though perfectly coun-
ter shaded, and colored brown or gray like the ground or tree trunks. Such
are many rats, mice, shrews, etc., and, among large mammals, lions, pumas,
wild asses, and many horned ruminants.

An interesting parallel between the disguising-equipments of mammals
and those of birds is furnished by the obliteratively marked young of many
species in which the adults are without markings. The special obliterative
costumes of young gulls and other birds was described in Chapter XIV.
Among mammals, some of the deer and wild swine are notable examples.
The adults are obliteratively shaded but unspotted, while the fawns and little
wild pigs are super-equipped with an obliterative pattern of light spots, which
lasts through their baby-time of comparative sluggishness and helplessness.
These spots belong to the class of generalized flecky background-patterns,
inclining on some fawns to sun-fleck and leaf-shadow picturing, and on pigs
to water-shine picturing. Some deer—for instance the European Fallow and
the Indian Axis Deer—retain the youthful pattern of obliterative flecks through
life. This simple, spotty pattern is connected by various intermediates with
other types of cervine and antelopine marking—such as the vertical bands
of the Koodoo, the bands, stripes and spots of the Harnessed Antelopes, the
- softly ‘ruptive’ and background-picturing broad patches of whitish on light
brown worn by the American Prongbuck (Antilocapra americana), etc. In-
deed, with mammals as with birds, the special types of marking are all more
or less smoothly connected one with another by intermediate types—worn,
for the most part, by beasts which are evidently intermediate in habits also.
But we have now mentioned and briefly analyzed the workings of the main

145

central types of mammalian picture-pattern codperant with counter shading,
as far as they are known to us. Wittingly and unwittingly, we have passed
by a multitude of minor variations and adaptations, and may even have
missed some types of foremost importance.

The next chapter deals mainly with the patterns of mammals which lack
diurnal obliterative shading..

146

Fic, 94. Mbega Monkey —a ‘ruptively’ and ‘secantly’ colored forest mammal. His light brush and long side-fringe carry
outward into his surroundings his sky-vista-like patch of light, which ‘cuts his form to pieces.’
Photographed from nature by C. G. Schillings. (Cf. Figs. 88-89.]

PLATE VIN

AHOEN & CO BALTIMORE.

EXPLANATION OF PLATE VIII

SUNRISE OR SUNSET.

-\ By Abbott H. Thayel. ,

Presenting the very colors of the Spoonbills..

! [See Plates IX and X.]

ROSEATE SPOONBILLS.
In morning or evening sunlight.
. By Abbott H. Thayer.

(See Plates IX and X.]

CHAPTER XXII

MAMMALS, CONCLUDED, ETC. PATTERNS OF MAMMALS THAT LACK DIURNAL
OBLITERATIVE SHADING. SKY-MATCHING PATTERNS OF MAMMALS, AND
A COMPARISON BETWEEN THEM AND THOSE OF BIRDS. FIXED ‘DAZZLING’
MARKS, AND OTHER SPECIAL PHASES OF PATTERN-USE

N strange contrast to the many beasts whose strongly, moderately, or
faintly patterned ground-matching costumes are based on full and perfect
obliterative shading, are the few whose bold, clear patterns seem to defy that
foremost obliterative law.* Such are the skunks (Mephitis, Conepatus, and
Spilogale) in America, the African Zoril or Cape Polecat (Zorilla striata),
the Madagascan Golidictis striata and G. vittata, and that queer, badger-
like stinker of the Javan mountains, the Teledu (M: ‘ydaus meliceps). These,
and many other small or medium-sized carnivorous mammals, are boldly
pied with white and black—or dusky brown—and their white is all on the
back and sides, while their under parts are uniformly dark.t We have here,
as far as these patterns go, a complete inversion of the regular obliterative
coloration. A true analysis of this case, which looks at first so mystifying,
shows it to be in truth merely one more phase and token of the infallibly close
correlation between animals’ costumes and their environment and habits.
Two diametrically different uses of white are equally consistent factors of
animals’ obliterative coloration. White on the underside, the usual culmina-
tion of the almost universal obliterative counter shading, serves as a neutralizer
of shadow, an adjuster and maintainer of the even balance between light and
dark; white on the upper side, as worn in various forms and proportions by a
good many animals, serves to imitate, to picture, the shining sky from which the
underside is shaded. On the one hand, it is an all-important ingredient in an

¥ See footnote, p. 123.
} The “white” of these animals is in reality pale yellow, brown, or gray.—A. H. T.

147

obliterative compounding; on the other it is used, at its face value, for direct
‘background’ picturing. Skunks, teledus, and the rest, long believed by natu-
ralists to be colored for warning conspicuousness (proclaimant of their foul
defensive equipment), have, in fact, the universal obliterative coloration.
Seen from above on open ground, as men commonly see them, they are some-
times very showy beasts, with their big, skylit patches of yellowish white, and
their darkly shadowed undersides. But how different is the view their ter-
restrial victims get of them! To these little animals—insects and small
vertebrates of many kinds—they commonly loom up against the sky, towering
high and huge as an elephant would above a skunk. Their big, bold patches
of white and black are then about as potently obliterative as a beast’s pattern
can ever be—as is proved by our photographs (Figs. 95-97). According to the
angle at which they are seen, their lustrous white * either nearly or exactly
matches the brightness of the sky, while their dark patches are left to look like
bushes, boulders, or more distant trees standing up above the horizon. All
this is attested beyond question by our photographs, as the reader will agree.
And he must consider that these pictures were taken in full daylight—a far
severer test of such an effect than the dim light of night. For at night, sky and
sky-pictures being correspondingly and greatly dimmed, the casual discrep-
ancies of shade between them are reduced to almost nothing. The whole
illusion, of course, is better in a dim light, since it depends wholly on bold,
simple counterfeiting of background ‘values’ or shades. Skunks, and most or
all of the other mammals that are colored like them, are grubbing terrestrial
hunters, and nocturnal, and hence are served by their boldly pied white and
black patterns in the manner shown by our pictures, but on the whole even
more potently, by virtue of the dimness of the light in which they commonly
hunt. The white stripe on the Common Skunk’s forehead and snout—a mark-
ing shared by several other grubbing ground-beasts, and among them some
with light colored bellies, e. g., the badgers (Meles and Taxidea)—plays an im-

* The actually pale yellow hairs are so lustrous as to look brighter, in such views, than lusterless
pure white could.

148

Ftc. 95, Common Skunk as he appears to mice, grasshoppers, and other small ground- Fic, 97, Mouse’s or Cricket’s view of the Common Skunk, as in Fig.
animals—his dark passing for distant trees, or bushes, his white for sky.

. 15, ete.
Photographed outdoors from a stuffed skin.
Photograph, outdoors, from a stuffed skunk-skin. (Slightly retouched.)

Fig. 98. Common Skunk, as in Fig. 97, but with sky ‘back-
ground’ cut off by dark, making his white conspicuous,

indistinguishable against the sky. [Ct. Fig.
95, ete.] ;

hot: : td tuffed skunk
Pl

kin,

Fic. 99. Conepatl or Prairie Skunk, scen from his prey’s point of
view. [Cf. Fig. 95.]
Stuffed skin, outdoors, photograph.

Fie. 100. Conepatl or Prairie Skunk, as in Fig. 99, but with sky back-
ground cut off. [Cf. Fig. 98.]

Stuffed skin, outdoors, photograph.

portant part in his disguisement. As he shambles over a field, with his seeking
snout held close to the ground, this white stripe, in the view of the little ground
beasts he approaches, ‘lets down the sky’ through his black head and fore-
shortened bulky body, splitting the apparition into narrow, un-beast-like halves,
which look like sticks or weeds or more distant bushes or boulders showing
above the horizon. The several variations in the form and proportions of the
sky-picturing white top-patterns of skunks and skunk-like beasts are all in
more or less obvious conformity with differences in their wearers’ ways and
places of life. ‘Thus the Common Skunk’s main white pattern has a somewhat
irregular, a waved and insected, lower outline; while that of the Conepatl or
Prairie Skunk (Conepatus mapurito, etc.) is square-cut and straight; and
these differences are doubtless, nay, obviously, matched by differences in
the beasts’ average backgrounds. For the eastern skunk is more often seen
against a sky-line broken by trees, stones, and bushes, than is his desert-
haunting relative. (Compare Figs. 99 and 100 with Figs. 95 and 98.) Al-
though these photographs are from shapeless stuffed skins, they can be trusted
in the matter of the main effects of the beasts’ patterns, and even the main
pattern-differences between the two species. Evidently, the Conepatl has
just so much of his back sharply and levelly cut off by white, as, in the aver-
age view of the little ground beasts he hunts, at the moments when it most
profits him to be concealed from them, would show above the (unbroken)
horizon. The pattern of the common eastern skunk renders the same serv-
ice, but with the difference that it represents a sky-line notched by trees,
etc., as we have seen. The Teledu of Java is marked much like the Cone-
patl, though its white ‘blanket’ is narrower. Other beasts with more or less
nearly the same habits, and the same general system of sky-picturing, are
the Ratels (Mellivora capensis and M. indica), the Wolverine or Glutton
(Gulo luscus) in some pelages, the Great Ant-eater (Myrmecophaga jubata),
the Tamandua Ant-eater (Tamandua tetradactyla), and, to some extent, the
Tasmanian Devil (Sarcophilus ursinus). But most of these beasts have
even browner (or grayer) ‘white’ patterns. Many of them, on the other

149

hand, like several of those previously mentioned (skunks and badgers), have
head- and face-masking as well as body-masking sky-picture patterns. Such
markings, indeed, are very common among grubbing carnivorous and in-
sectivorous mammals. Anyone who will seek through a big museum col-
lection of mammals will be able to add many cases of both sorts to the above
casual and fragmentary list. The profusely striped top-pattern of the
Spilogale and the Zoril, etc., is merely another form of the same costume,
and performs nearly the same service. It pictures sky seen through obstruct-
ing twigs or narrow leaves, and is, with little doubt, significant of more sylvan
or bush-land-haunting habits on the part of its wearers. It looks somewhat,
also, like the converse of such a sky-scene—sharply contrasting linear lights
and shadows on the ground, in moonshine. But the light markings, being
almost white, are over-bright for this ground-picturing service, whereas they
exactly fit the other. True, the effect of such brilliant, sky-lit stripes, con-
trasted with the shadowed black of the under parts, is powerfully ‘ruptive’
in all views, even against the ground, ‘breaking the beast up’ into un-beast-
like stripes and patches. Indeed, against the most brightly moonlit and
most sharply shadow-brindled ground, such a beast must be pretty well ob-
literated, and even his motion may be masked,—by the motion of the ground-
shadows, cast by wind-swayed vegetation. But such conditions are highly
occasional, and against open ground the spilogale’s mantle of white stripes
must often reveal him, especially when he moves about. It would seem that
he might be much better equipped for concealment in almost all such views
if he were counter shaded and more softly striped—or mottled, or even wholly
unmarked. Think how ghostly-illusive against moonlit ground are the ob-
literatively shaded and faintly patterned hares, and kindred beasts! Ap-
parently, the dominant use of the spilogale’s pattern is not ground-picturing,
but the matching of sky glimpsed through dusky obstructions—a purpose
which the obliteratively shaded, dimly patterned animal’s costume could by
no means serve. (See Fig. 103.) The spilogale probably has few large
enemies to fear, and—just as with skunks, teledus, etc.—it is evidently of most
150

Fic. 101. Spilogale, or Little Striped Skunk, seen from mouse’s and cricket’s position—his dark
stripes passing for vegetation, and his white stripes for the sky. [Cf. Figs. 95-99.
Stuffed skin, outdoors, photograph,

Fic, 102, Spilogale, or Little Striped Skunk, seen from men’s and hawks’ point of view. [Cf Fig. 101.]
Stuffed skin, outdoors, photograph.

Fic. 103, A Compound Picture. (Photographic, except for the upper rear-view of the Hare. The
crouching Hare was photographed from life; the Skunk from a stuffed skin.) ‘This picture, by show-
ing the ola familiar type of obliterative coloration alongside of the obliterative effect of white upper-
surface patterns, so long supposed to make their wearer couspicuous, prepares the reader to discover
that all patterns and colors whatsoever, of all animals that ever prey, or are preyed on, are, under
certain normal circumstances, obliterative. Animals which need to escape notice when looked at
from above, match the ground. Those that must not be detected when looked at irom a lower level,
match the sky, or whatever combination of sky, vegetation, etc., commonly forms their backgroun
from this view-point. Between these two axteanoleitwe count sky and sky-reflected-in-water as one—
are ranged the color-schemes of most of the animal kingdom.

In this illustration the Skunk against the sky loses the white parts of his silhouette, and his dark is
left to look like bushes, ete., in the background (4). On the other hand, the Skunk against the ground
loses his dark parts, and his white, though often, as here, conspicuous in itself, has a largely inorganic and deceptive contour, and, when seen
amid obstructing twigs and leaves, especially at night, is potently obliterative (Cf. Figs. 104-106). It is in fact not pure white, but
nearer to the color of bleached dead leaves and twigs. The Leaping Hare’s white rump vanishes against the sky (C), from the sight
of the creeping fox, or other quadruped pursuer, The fox’s eyes are, at that moment, lower than the Hare’s tail, and he sees it
against the sky, (or, in the woods, the sky’s light through the leaves). (J) shows a man’s view of the same hare, and explains why men
have thought this white conspicuous. To a young hare this white rear of the mother would present the same difficulty as to the fox. On
the other hand, a crouching Hare, so admirably merged into his surroundings when looked at from above, (), is boldly conspicuous
when seen from the position of a mouse or cricket, as in (#7), and in the detached figure of a Tame Hare, (G@). Ifa mouse could theorize,
he would know the skunk to be obliteratively colored, but would consider the hare, execpt when it was running away from him, a most
conspicuous animal, thus reversing men’s notions. In this illustration, the hare in_ profi

: St I D le against the sky would be still more convincing
were his members extended for action, showing a more revealing outline. [Cf. the Domestic Hare (@).]

importance to him to be masked for the eyes of the little ground beasts on whom
he feeds. (See Figs. 101-102.)

Seen against snowy ground, which is common enough through a large part
of the eastern skunk’s range, a boldly pied pattern of white and black, such
as he wears, is of course most potently ‘ruptive.’ But it does not truly oblit-
erate, because all the black part of the beast is left rankly conspicuous, and has
too peculiar a form, in such a view, to be easily ignored, or mistaken for a land-
scape-detail. Northern skunks, however, vary a good deal in pattern, and
the very whitest of them are doubtless well disguised, in certain views, against
showy ground, ‘particularly amid trees and sticks and stones and bushes
and other inanimate dusky details. In this case, as throughout the whole
great field of phenomena we are studying, it stands to reason that a special
development of costume must serve minor as well as major ends.* But how-
ever potently ‘ruptive’ (and therefore essentially obliterative) in their effect
when seen against the ground the whitish patterns of skunks and skunk-
like beasts may sometimes be, the paramount function of these patterns is
certainly the picturing of sky, as our figures show (Figs. 95-103). Both
uses are served, perhaps almost in equal measure, but with the balance of
importance probably tipped somewhat toward the ground-matching function,
by the wholly or almost wholly white costumes of several snow-land animals.
Such—to begin with those least remote from the skunks—is the rare, bear-
like Ailuropus melanoleucus, of Thibet; such are the Arctic hares and foxes,
the boreal weasels and some of the boreal hares, and the Polar Bear. Almost
all of these, and their counterparts among boreal and Arctic birds—the ptar-
migans, the snow buntings, the Snowy Owl, and the White Gerfalcon—almost
all of them, mammals and birds alike, have a few sharp black markings in their
mainly immaculate white costumes. These evidently serve as what may be
called ‘distractive’ or ‘fixed dazzling’ marks. They are, in most cases, too
small to show except in a very near view—when, by their sharp but isolated

* Or, in terms of the Natural Selection theory, that each development is the product of the sum
of all its uses, big and small.

e I51

and noncommital conspicuousness, they tend to draw and hold the eye’s
attention,—in a sense, to dazzle it, so that it less readily discerns the faintly
shown snow-white body of their wearer. The working of this principle is
illustrated by Figs. 104-106. Most ptarmigans have black tails, which, folded
and largely hidden by white ‘coverts’ when the bird is skulking, show as nar-
row, sharp black marks, drawing the eye to a point away from the bird’s
rotund body, ‘dazzling’ it slightly, and presenting it with a view of what
might be a little twig or stone or other dusky landscape-detail. Some ptar-
migans in white winter plumage have also a black face-mark, which serves
the same purpose, and also masks the bird’s round and lustrous eye, in the
manner explained in Chapter XIV. The Snowy Owl and the White Ger-
falcon are more profusely flecked with ‘distractive’ black marks. Notwith-
standing the special inherent ‘dazzling’ function of such markings, they all
belong essentially to the ‘picture’-pattern class. For, if they did not also
look like dark landscape-details, they would in the long run tend to reveal
rather than conceal their wearers. ‘The northern weasels in their white winter
dress have ‘distractively’ jet-black-tipped tails. Polar Bears and Arctic
Foxes have no such markings, unless we count their black snouts and dark
eyes. Very likely such beasts when they are skulking partly close their eyes,
masking their too characteristic circular or oval form. The little Thibetan
Snow Bear (Ailuropus), on the other hand, has more than a mere ‘distrac-
tive’ display of black in its white costume. Its legs, its ears, and a narrow
shoulder-mantle are solidly black, and it has black spots around its eyes.
Thus it is well fitted for obliteration. or great inconspicuousness against
either snowy ground or sky, in a country full of dark boulders or bushes,
or both.* In much the same manner, and presumably for life amidst back-
grounds of the same general aspect, is the Kamchatkan white-shouldered Sea
Eagle disguised. But in his costume the dark preponderates over the white.

One more principal phase and function of mammalian sky-matching
costume remains to be described. That is the ‘obliteration’ of fleeing deer,
* The white breast-marks of several of the black bears belong in this same class of obliterative patterns.

152

Fie. 104.

Fie, 105.

i illustrate the obliterative effect on faintly-showing contours of sharp and strong internal marks. The
altri one, 2 ay pone cep i that the Butterflies’ or Letters’ contours near the bold marks vanish, while those apart from
aaaekiugs remain perfectly distinct. The markings, at the same time, ally themselves to kindred details in the background,

Fie. 106.

Fie. 106. Here the spectator will discover, if he recedes far enough, (seven or eight yards in a bright light) that all three of the
monochrome butterflies, even the dimmest, can be seen further, or in a less illumination, than the normally and brightly patterned
one. This latter fades first. This shows how contrasted juxtaposed color-notes efface each other, so that contrary to the old theories
they are not so good as monochrome for revealing the weare:

M r, even in the open, while, seen through the average tracery of out door
vegetation, they almost guarantee disguise and concealment. See Plate V.

antelopes, hares, etc., by white tails and rumps. More characteristic even
than the grubbing carnivores’ sky-matching head-patterns are these more or
less ‘eclipsable’ rear-end flight-masks of timid, fleet ruminants and larger
rodents. When these beasts flee at night before terrestrial enemies—which are
nearly always of lower stature than their quarries, and in most cases addition-
ally fated-to look upward at them by the fact of the quarry’s high-jumping
gait, and their own crouching and slinking—when these hunted beasts flee
thus, their brightly displayed sky-lit white sterns blot out their foreshortened
bodies against the sky. In the night, the illusion must often be complete,
and most beneficent to the hunted beast, who by its aid may often just avoid
the lion’s or the tiger’s or the cougar’s or the cheetah’s killing second spring ;—
vanishing into air, as it were, before the predator can get his aim for the leap,
or before he can perceive the direction of his quarry’s flight. For photographic
illustrations of this marking’s obliterative effect, see Figs. 107-115. Such
rear-end sky-pictures are worn by most fleet ruminants of the open land, and
by many rodents with more or less nearly corresponding habits—notably
the hares, and several smaller running or leaping rodents whose terrestrial
enemies are many of them beasts of low stature—like weasels, minks, snakes,
etc., and foxes, that slink and crouch. The ruminants that lack such mark-
ings are most of them either extremely big and powerful—like some of the
huge African antelopes, and almost all the bovine beasts—or else they live in
dense tropical forests, where at night there is very little ‘overhead’ light for
them to relieve against. Some of the little South American jungle deer are
good examples of this forest-haunting class.

All these various sorts of wonderfully effective sky-picture patterns are
worn by animals that are habitually or most commonly looked up at, either
by their enemies or by their quarries. Indeed, the presence or absence, the
high or scanty development, of such markings in an animal’s pattern, seems to
be a direct and accurate indication of whether, in the average view of the
creatures from whom it most profits the animal to be concealed, it comes above
or below the horizon line—and of the largeness of the preponderance in either

153

direction. Thus gulls, terns, and many other sea birds, which fly between
blank ocean and blank sky, getting their food from the water, are largely
cloaked in sky-matching white. So, among land birds, are the often-men-
tioned Snowy Owl and White Gerfalcon, which fly and hunt over treeless
barrens and the bare ocean-shore. So are most swans, some geese, some pel-
icans, and several herons, storks, ibises, cranes, etc..—birds that swim or
wade, seeking their food below them in the water, and doubtless subject, in
all or most cases, to persecutions from aquatic enemies. Showy as these
birds are against the muddy ground and dark-green vegetation, they are
equipped for the utmost possible inconspicuousness when seen from below,
against the sky. Viewed at the proper angle, they must, like the skunk’s
back, be almost invisible, especially at night. (An opaque body directly in-
ter posed between the beholder and the zenith cannot fail to show dark, however
colored; but the upper surfaces of a snow-white opaque body looked at in an
obliquely upward direction, so that it is seen sky-lit and at the same time
against the sky, may exactly match the brightness of its luminous background
—all of which is shown by Figs. 107-115.) Plates VIII, IX, and X,
with their Flamingoes and Roseate Spoonbills, reveal the simple fact, which
seems never to have been noticed, that these traditionally “showy” birds
are, at their most critical moments, perfectly ‘obliterated’ by their colora-
tion. Conspicuous, in most cases, when looked at from above, as man is apt
to see them, they are wonderfully fitted for ‘vanishment’ against the flushed,
rich-colored skies of early morning and evening; and such are their normal
backgrounds, at their chief feeding-times, in relation to their aquatic enemies
(sharks, alligators, tortoises, anacondas, etc.) and those of their prey that
see at all. Of course, against the dawn or the sunset itself, these birds must
show dark, just as with white against the zenith; but the rosy hues very com-
monly suffuse both sides of the sky, so that, in either twilight, the Spoonbill’s,
Ibis’s or Flamingo’s adluminated ruddy color very often has a true ‘back-
ground’ of illuminated ruddy sky. Further, the side of such a bird actually
sunlit, at early morning or late afternoon, is made to glow so brilliantly as to

154

Fie. 107. Prong-Buck as commonly Fic. 108. Prong-Buck’s obliterative Fie. 109. The same as Fig. 107, but with the
seen by all animals whose eyes are on a rump-mark seen against the ground, as Prong-Buck’s legs and the landscape shaded
lower level than its rump. (This, of course, men see it, their eyes being on a higher more nearly into one flat ‘tone,’ such as the
includes the Prong-Buck’s terrestrial ene- level. beholder would really see in the night. Body
mies, such as wolves and cougars—not to Photographed from a stuffed skin. and legs, not coming against sky, would, at
speak of the beast’sown young, which have Soiled rump-mark covered with white rabbit skin. night, be invisible, or very nearly so.
been supposed to use their parent’s snow- ature, in such cases as the Hare’s and Prong-
white stern as a ‘banner’ to follow in Buck’s, evidently ‘obliterates’ with white exactly
flight.) 5 as much of the animal as his carnivorous enemies,

n all these photographs from a stuffed when close upon him, would see against the sky,
beast, the rest of the animal is much more to guide their final leap.
conspicuous against the ground than it Retouched photograph of stuffed skin.

would be in nature.
Photographed trom a stuffed skin,
Soiled rump-mark covered with white rabbit skin

Fie, 110, Prong-Buck against the sky, presenting a con-
spicuous silhouette of all bué the rump-mark, which would
show were it of any darker tone than white.

Soiled rump mark covered with white rabbit skin.
Photograph of stuffed skin.

(Except where the contrary is expressly stated, all our photographs are
absolutely unretouched.)

Fic, 111. The common aspect of animals showing against night sky, if they have no white top-patterns.

Fig. 112. (Dead) Northern Hares seen from
the level of a creeping fox.

These photographs show that from this view-
point the so-called banner-mark, the white, is
precisely what does nof show.

Vic. 113, Dead Northern Hare, seen from men’s level.
Hares in danger from over-head foes, e. g., birds of prey,
doubtless resort to crouching ‘invisible’ rather than to run-
ning, while, on the other hand, enemies which trail them
force them to leap away.

Photographed, out-doors.

Fig. 114. White card, as in Fig. 115, but invisible against the sky, because the camera was lower than
the card, just as a panther or fawn would be lower than the deer’s buttocks.

Photograph.

Fie. 115. A white card—as it were a detached rump-mask against the ‘ground.’
Photograph,

look like a real sunset or dawn, repeated, on the opposite side of the heavens,—
either east or west as the case may be.

' All these white and pink (or red) fishing-birds and vegetable-eaters have
the habit of staying more or less quiet, for longer or shorter periods, in the
near vicinity of their aquatic prey and enemies. Egrets and white herons
stand hour-long motionless or wade cautiously about in shallow ponds, rivers,
lagoons and estuaries,—ready with poised head and lancelike bill to stab the
first fish or frog that comes within their reach. (See Figs. 116-118.) White
pelicans fish while swimming; but the brown pelicans plunge headlong from
on wing into the water, catching their prey by violent abrupt assault, like
the gannets, the terns, the kingfishers, and the Osprey; and all these plunging
fishers have characteristics of coloration in common, which are not typical
of the stealthy fishers. These consist in brilliant ruptive patterns, chiefly on
the head, but sometimes also on the wings and body—patterns which doubtless
have the effect of confusing the suddenly assaulted quarry as to the exact
position and the true form of its attacker. Such are the tern’s black head-
caps, the black or dark marks about the base of the Common Gannet’s pale
sea-green bill, the clearly-contrasted brown and white stripes and patches
of the brown pelicans’ heads, the motley costumes of kingfishers, etc. At
the instant of attack, such markings ‘break up’ and confuse the apparition
of the attacker, doubtless often to the bane of the attacked, whose life or death
must often depend on the turn of a hair toward quicker or slower, surer or less
sure darting off. Stealthy fishers, on the other hand, would in many cases be
misfavored by such ‘ruptive’ markings, which during their quiet stalking and
watching would increase their conspicuousness against the sky. On the
other hand, even the black wing-tips and like markings of gannets and other
plunging fishers, serve as ‘dazzling’ and ‘distractive’ marks,—like those
of. the tails of winter ptarmigans and weasels—at the moment of the bird’s
arrowy arrival with part-folded wings (and tail) among his finny prey.

Then there are two or more classes of animals merely patched with sky-
pictures. Such are the more or less largely white-backed skunks, and kin-

155

dred mammals, and the many arboreal birds and several arboreal mammals
which have biggish white spots or patches on their backs and sides. The
ground beasts of this group are, as has been explained, specially equipped
for concealment against the horizon-bordering sky; while the tree birds’ and
tree beasts’ more or less ample, irregular patches of sky-picturing white are
in evidently just proportion to the greater or less amplitude and frequency, in
their average backgrounds, of sky vistas, and light foliage vistas amidst dark
leaves and twigs and tree trunks.

Next and last in order come the terrestrial and semi-terrestrial birds and
other animals which are equipped for concealment against the landscape below
the horizon, and have little or no hint of sky-picturing in their costumes. Such
are many woodland ground birds, notably the brown tropical ones described
in Chapter XIX. Such also are most of the terrestrial woodland mammals;
such, again, are snipe, goatsuckers, and many of the small, close-lying Gal-
line (most arboreal species have fragmentary sky-pictures—see the Cock
Ruffed Grouse in Plate II); such are most frogs and toads and many ground
lizards; such are sand crabs; and such, in the most marked degree, are many
terrestrial snakes—for instance the Copperhead, shown in Plate-XI (Chap-
ter XXIII). Most of these creatures are patterned with elaborate ground-
pictures, and on some species, like the Copperhead snake, these have reached
a very high degree of specialization. Because of their low stature and their
ground-haunting, close-lying habits, such animals as these scarcely ever, in
the view of predators or quarries, stick up above the horizon line. They are
colored, with exquisite efficiency, for obliteration or extreme inconspicuousness
when looked down at, against a background of mother earth and her lowly
vegetable mantle. If men were Lilliputians, and looked up at the flanks and
back of the Copperhead snake, as in reality they look down at the sky-pic-
turing back-pattern of the piebald skunk, the snake’s coloration would seem to
them just as ‘‘conspicuous” and inappropriate for disguise as the skunk’s has
always seemed. ‘‘It’s all in the point of view;”’—and if we would learn the
true, the compellingly apparent significance of animals’ costumes, we must

156

EXPLANATION OF PLATE IX

ROSEATE SPOONSBILL. °

Before sunrise or after sunset; matching the sky behind it,
(i. e., the western sky at dawn, or the eastern sky at sunset).

SUNRISE OR SUNSET.
A typical sky, much like the aspect of the Flamingoes.

en FLAMINGOES. ;
mee, 7 ote, rea Ryans a ual
Before sunrise or after sunset, oes the ty,

; behind them, as in the Spoonbill picture. ' "tis angio?

BBs

By Abbott H. Thayer

These various sketches of Flamingoes and Spoonbills show how wonderfully such birds match
or reproduce the colors of morning or evening skies to the eyes of the inhabitants of the water in
which they: wade—both their enemies, such as anacondas, alligators, sharks, etc., and such of
their prey. as can see them.

Commonly, the bird’s upper outline ‘melts’ into the sky, leaving the rest of his contour, seen
through the Water, agitated and muddied by his feet, to be lost i in the indeterminate color-mass of
the flock. Shaken and jumbled ’ by the continual agitations of the water, the image of the flock
retains, for eyes beneath the surface, only its color and. its position, both of which coincide with
those of the dawn or sunset, (though on the other side of the heavens) or the flushed sky opposite.

Through all stages of twilight this living mass, seen against the less lighted parts of the sky,
blends into. it, undergoing kindred ehanges of illumination, and when full sunlight bathes it, its
lighted side blazes out into a perfect representation of the dawn or sunset itself, though in the
opposite quarter. In the case of the Red Flamingo the bird’s legs, including its feathered thighs,
are purplish instead of orange-red, in. keeping with the color-gradation of the sky, which is, at
these hours, commonly purplest ‘at the lowest point, having its purest reds and oranges a little
highér. up. Thus, each part of the bird has every possible opportunity of matching its
background, —A. H. T.

PLATE 1X

AWOEN & GO, BALTIMORE |

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APRS MAES

WERE sed ona

Fi¢, 116, Imitation Egret without plumes
photographed against white (substituted EC
sky), to show that the shadows whic
reveal the form come at the very points
normally covered, at the breeding-season,
by the so-called ‘‘nuptial”’ plumes. These

ints are indicated by the arrows. The

nifelike thinness of the throat, where

plumes would incommode him, largely
obviates the need of them at this point,
by minimizing the shadow.

Fic. 117, Imitation egret in nuptial dress,
photographed against black, to show the
position of the plumes.

Fig. 1184. 4 isasectionot the Egret. F
the roof-like plumes. ¢' the dark under side-
which they hide. ‘he part of a heron’s
neck that normally bends backward as he
stands has the roof’s ridge-pole in fron/, and
the caves behind.

Fic. 118. Imitation Egret in nuptial plu-
mage, photographed against white, showing
the effect of the plumes in effacing the shad-
ows, thus rendering the bird almost invisible
when seen peainst thesky. This is achieved
on the model, as on a real Egret, in the only
conceivable way: the plumes extend down-
ward and outward like a roof between the
beholder’s eye and the shadow to be covered.
Because of this roof-like position, they stay
illuminated throughout their whole length,
and interpose their bright fringe between
the beholder and the shadowed undersides
of the neck and body. The fact that these
fringes cross the bird’s contour, and follow
that of the vegetation in which he stands,
greatly helps the concealment. White fluffs
or fringes of this general character, screening
the too deeply shadowed abdominal space,
between the legs, are very common among
birds and mammals.

first learn to look at them not solely from the point of view of man, who neither
flies nor climbs nor crawls, but also from that of the other animals, big and
little, winged and creeping, with whom the bearer of the costume in question
has in any way to deal. And by no other phenomenon of obliterative colora-
tion is this fact so forcibly brought home to one’s mind as by the perfectly
consistent and unbrokenly intergraded chain of sky-picturing and ground-pic-
turing patterns and costumes of birds and mammals.

One more notable phase of sky-picturing’s occurrence on birds must here
be cited, namely, its part in the costumes of some ground birds of the open
land. The American Bobolink (Dolichonyx oryzivorus) for instance, in the
summer plumage of the male, is marked and colored much like a skunk—as
its colloquial name ‘‘Skunk Blackbird” attests. Roosting at night in weeds
and grasses some inches above the ground—as it almost certainly does—it is
disguised, for the eyes of prowling predators, almost exactly as the skunk,
himself a prowling hunter, is disguised for the eyes of smaller ground animals.
The Black Lark Bunting (Calamospiza melanocorys) of middle western North
America, likewise a bird of the open ground, has a big, sky-matching white
patch on its wings; and several Longspurs (Calcarius, etc.) and Larks (Alau-
did@) have markings of the same nature, and kindred habits.

Sky-picturing marks are sometimes found in evident codperation with
wholly different disguising effects. Thus the common American Raccoon
(Procyon lotor) has a rim of white or very pale brown bordering its largely
dusky face; and though in many views this must serve as an obliterative sky-
matching mark, like the many kindred markings of grubbing carnivorous and
half-carnivorous mammals, yet it also admirably serves to make the Raccoon’s
whole face and head, in front view, look like the end of a hollow log or stump,
with a shadowy, dark interior and light, encircling outward rim. (See Fig. 120,
No. 36.) This trick of coloration, which has already been mentioned in con-
nection with the sloths (Chapter XX), is of widespread and frequent application
in the animal kingdom, as a glance at Fig. 120 will convince the reader. Here
we have many kinds of ‘holes’ with encircling light rims or margins; some

157

of them real and some imitated—pictured—by the surface-patterns of animals.
Some of these counterfeits are very highly developed and effective (e. g., the
whip-poor-will, No. 50), while others are comparatively obscure. But even so
casual a rendering of this effect as is achieved by the young owl’s face (No.
1) may well benefit the animal that wears it, in the long run—since it tends
to mask the creature’s true structural form and look of life.

A good many mammals * have the form of ‘distractive’ coloration men-
tioned in the case of pheasants, etc. (Chapter XVII), namely, strongly banded
tails and delicately marked (or unmarked) obliteratively shaded bodies.
Almost all are beasts that live in holes, and dart into them in time of danger;
and their banded tails undoubtedly work for their safety by diverting the pur-
suer’s attention and attack to a point behind them, in the essential moment of
their darting forward into their retreat. Even if they are actually seized by the
tail, they may still tear free and escape—whereas a body-grip would far oftener
succeed. When such beasts are quiet, their tail-bands act obliteratively, to
the full—as we have already seen in the case of birds (Chapter XVII).

We have now examined what seem to be the main principles and many of
the chief phases of disguising coloration among mammals. But, as I said
before, it is likely, nay, certain, that many types of particular interest have
escaped the notice of my father and me. It is true also that we should be ad-
venturing beyond the proper scope of this book if we tried to give more than a
clear sketch, illuminated by a few chosen representative details, of any one
branch of the big and intricate general theme. Our next subjects—fishes,
reptiles, and batrachians—must be considered even more briefly, owing to
our very fragmentary knowledge of these animals.

* Spermophiles, lemurs, raccoons, etc., etc.

158

KiG,

Fie, 119—(.)

“Fie, 119-4.)

119—(2.)

Fic. 119. Diagram to illustrate the effect of the animals’
markings shown in Fig. 120. ‘These four figures show a
graduated development from No. 1, which represen 's nothing
substantial, to No. 4, which represents an edge of substance
showing against a shadowed cavity beneath. Animals’
markings, almost invariably, are on the general principle ot
No. 4.

Fic. 120. Bits of animals’ patterns, all repre-cuting holes,
i.e, shadowed cavities over which sharply detincd edges
“relieve” (like wood, leaves, rocks, etc). Among these are
mingled reproductions of actual holes to show how close
is the resemblance. (See Fig. 119.)

INDEX TO FIG. 120

. Young Barn Owl's face. Photo.

. Bit of Boa’s pattern. Photo.

. Baby Woodcocks’ (Philohela minor) backs and heads. Photo.
. Hollow among stones. Photo.

. Hollow among stones. Photo.

. Part of adult Woodcock’s head. Photo.

. Bit of Whip-poor-will’s back, Photo.

. Bit of Rattlesnake's pattern. Photo.

. Slivers of wood over shadow. Photo,

. Hollow among stones. Photo.

. Curled leaf. Photo.

. Bit of Ocelot’s pattern. Drawing from photo.

. Bit of Python’s pattern. Drawing from photo.

. Bit of Ocelot’s pattern. Photo. from half tone.

. Split bark over hollow in a tree. Photo.

. Bit of Whip-poor-will’s back. Photo.

17, Adult Woodcock’s eye. Photo.

. Top of baby Woodcock’s head. Photo.

. Fore part of a sphinx caterpillar. Photo. from drawing.
. Open mouths of young birds. Photo.

. Bit of Rattlesnake’s pattern. Photo.

. Bit of Copperhead Snake’s pattern. Photo.

. Shadowed holes in a crumpled hide. Photo.

. Markings on a kind of frog. Drawn from photo.

. Fold in a hide. Photo.

. Slivers of wood over shadow. Photo.

. Bit of Woodcock’s pattern. Photo.

. Bit of Copperhead Snake’s pattern. Photo,

. Baby Woodcock’s head, etc. Photo.

. Shadow between mushrooms. Photo.

31. Bit of Boa’s pattern. Photo.

32. Cracks among rocks, and Ptarmigan chick,

33. Bit of Rattlesnake’s pattern. Photo.

34. Holes (insect borings) in a board. Photo. from half tone.
35. Head of sphinx caterpillar. Photo. from drawing.
36. Raccoon’s face, Photo.

37. Bit of Ocelot’s pattern. Drawn from a photo.

38. Bit of the Serval’s pattern. Drawn from a photo.

39. Baby Woodcocks’ heads, etc. Photo.

40. Big knot-hole cavity ina tree. Photo.

41. Big knot-hole cavity in a tree. Photo.

42. Holes in a (tanned) hide. Photo.

43. Holes in a (tanned) hide. Photo.

44. Meadowlark’s breast-mark. Photo.

as. Hole in an old boot (moccasin). Photo.

46. Part of a feather from a female Golden Pheasant’s tail. Photo.
47. Torn dead leaves. Photo.

48. Torn dead leaves. Photo.

49. Torn dead leaves. Photo.

50. Head (crown) pattern of the Whip-poor-will. Photo.

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159

CHAPTER XXIII

FISHES. THE MOST UNIFORMLY AND NEARLY INVARIABLY COUNTER SHADED
OF ANIMALS. THEIR COLORS AND PATTERNS. OTHER MARINE ANIMALS

HOUGH my father and I know next to nothing about fishes from the
standpoint of systematic science, we have yet gathered, from lifelong
observation of them in their element, in market stalls, in museums, and (pic-
tured) in books, a trustworthy general estimate of the main characteristics
and prevalences of their disguising coloration. As a class, they are in some
respects the crowning vindication, or rather natural demonstration, of the
great law of obliterative counter shading. For while in each of the classes of
vertebrate land animals the exceptions to the employment of this principle
are, in the aggregate, many, despite the vast preponderance of the species on
which it is used, among fishes the exceptions are so extremely rare as scarcely
to count at all. This is true, at least, of the fishes that live within the reach
of daylight, as do almost all the kinds familiarly known to man. Cave fishes,
living in absolute darkness, are blind and colorless—dull white, i. e., simple
fish-flesh color, all over. Deep-sea fishes, though they live in perpetual night,
are as a rule neither blind nor wholly without superficial color. They are
sometimes whitish all over, like the cave fishes, but oftener monochrome
gray or brown, without special shading, though sometimes marked with red.
Thus there can be little doubt that despite the total want of daylight in the
waters they inhabit, they habitually see and are seen! The solution of this
enigma is the fact that the fishes and other deep-sea animals make and emit
phosphorescent light. How generally and how largely this is accomplished
we can judge only by the physical evidence furnished by the fishes’ eyes and
surface-colors. But it goes almost without saying that this ‘home-made’ (!)
160

light, by which the deep-sea fishes hunt and flee one another, is not such as
could favor any system of obliterative shading. For it has no prevalent direc-
tion relative to the fishes, but is erratic and forever shifting, striking all their
sides and planes with equal frequency. Accordingly, though colored, they
are mainly monochrome, and as dark below as above. But aside from these
little-known fishes that inhabit the remote abysmal depths of open ocean,
and the few kinds of blind fresh-water cave fish, practically all the species
known to man live in water permeated by the descending light of day.
Fishes, in fact, as man knows them, are, typically, inhabitants of the bright
upper and outermost border of the water, just as birds and butterflies are
dwellers in the bright-colored upper and outermost fringe of the earth. These
normal daylight fishes may be grouped, for our present purpose, in two main
classes,* namely, the Free-swimmers of open water, and the Haunters of sub-
merged land. ‘This second class is again divisible into many general types,
whereas the first is wonderfully homogeneous and simple. Wherever the
element of Jand enters into the case, there begin the chances of almost limit-
less diversification in the adaptive development of the fishes’ habits and col-
oration. But the conditions and aspects of water alone (especially beneath
the surface) are, comparatively, fixed, few, and simple. Correspondingly
constant and simple is the color system of the free-swimming fishes, both
fresh-water and marine. Their smooth, regular forms, monotonous habits,
and single method of locomotion all work in the same direction—all lend
themselves fully to plain obliterative coloration, founded on pure and perfect
obliterative counter shading. The gradation of shades and tints—from sil-
very-white bellies to dusky backs—on almost all free-swimming pelagic and
fresh-water fishes, is true and delicate and exquisite beyond description.
Among fishes of the same general form and habits, however distantly related,
this obliterative shading varies scarcely at all from species to species. Even
their color-tones differ but little. ‘They almost all wear exquisite, soft, water-

* Corresponding to the divisions called ‘‘Pelagic” and ‘‘Shore” fishes in ichthyological classi-
fication of the fishes of salt water.

161

colors—green, olive, gray, pearl-blue, silvery, deep olive-brown, etc. These
tints are all components in the obliterative shading and its resultant uniform,
soft, water tone, and have, in general, little independent pattern-effect. The
bar of silvery blue on a salmon’s side, for instance, does not flash out in its
full brilliance until the salmon, in executing some swift manceuver, turns his
side upward toward the daylight for an instant. At other times, in the nor-
mal position, it is merely a link in the obliterative chain of graded shades,
looking almost uniform alike with the salmon’s actually dusky back and his
actually white-silver belly. But any ‘liquid’ tinges of more vivid color
which these iridescent areas do superimpose on the general ‘flat’ and mono-
chrome effect, in the fish’s normal position, help his apparent dissolution into
his watery background of slightly mutable and varied tints. They are the
open-water fish’s markings, as it were—his pictures of vague, intermingled
water-tints. At and near the surface, there is more variety. Bubbles, and
foam, and flickering, shadowy ripples, seen from below—as well as dimmed
vistas, farther or nearer, of sky and clouds and sky-lit wave tops—all play a
part in the regular backgrounds of surface-swimming fishes, and all are re-
peated, more or less plainly, in their fair, sheeny coloration and faint pat-
terns. Most free-swimming, open-water fishes, indeed, spend much of their
time very near the surface (many are even wont to leap, and a few to jly,
above it—as everybody knows), and the delicate brilliance of their shimmer-
ing water- and sky-colors is in harmony with such habits. Another important
function of their lustrousness is the actual mirroring of water—one more
potent factor in their wonderfully efficient concealing-equipment. All brightly
shiny fishes—mackerel, herrings, salmon, etc.—mirror their surroundings in
this way. But even this beautiful principle is wholly subservient to the
obliterative shading, and does not upset the essential balance of its working.
‘Secant’ and ‘ruptive’ patterns are not common among these fair-colored
free-swimming fishes, but neither are they altogether lacking. The mackerel
has a seamed “lateral line” which serves as a ‘secant’ stripe, and many
wavy up-and-down stripes above it. A good many pelagic and fresh-water
162

fishes have one or more such markings, either longitudinal or vertical. But
patterns of this sort seem less appropriate to an environment of water alone
—particularly away from the surface—than to one in which there is some
element of ‘land’; and when they occur on free-swimming fishes they
may be connected with their wearers’ need to haunt the bottom during the
breeding season. Blotchy ‘ruptive’ patterns are almost wholly wanting
among these fishes. ‘They occur, however, on a few pelagic animals of gigan-
tic size, namely, on certain whales—and possibly on some huge pelagic fishes
also, though we do not know of any that are thus marked. Many of the
giants among pelagic (free-swimming) fishes, such for instance as the sharks,
are colored rather dingily, lacking delicate tints and lustrousness—though
almost all obliteratively shaded to the full.

We now come to the second and more composite class of daylight fishes,
the haunters of submerged land. That is, the fishes that spend all or the
greater part of their lives in close contiguity with submerged solid portions
of the earth—whether rocks, sand beds, coral reefs, or muddy and pebbly
lake and river bottoms. They are, so to speak, the sparrows and partridges
of the water, as the free-swimmers are the gulls and swallows. More than
this, the submerged-land-haunters are also the parrots, toucans, and para-
dise birds of the water. Man’s knowledge of subaquatic life and scenery is
at the best pitifully inadequate, but ‘he is able to piece out his few, fragmen-
tary, and imperfect observations * of wild fishes in their element by an ac-
quaintance with some indubitable general principles of their coloration and
illumination, and by a comparison of fishes removed from the water, and in
aquarium tanks, with terrestrial and aérial vertebrates. The conclusions
reached by such means must necessarily be defective—very far from com-
pletely rounded—but they will yet be approximately correct as far as they
go. To the student of obliterative coloration, who has learned to perceive
the exquisite correlations between animal and environment which prevail
among the creatures of earth and air, the examination of such ground-haunt-

* Subaquatic photography is destined to be of great service in this direction.
163

ing fishes as may come into his hands is the key to a new and strangely beau-
tiful realm of natural scenery, which must otherwise have remained almost
wholly unknown to him. For there can be no reason to doubt that the oblit-
eratively shaded bodies of these fishes are covered with true pictures of their
mysterious natural environment, so far withdrawn from human ken. Pos-
sibly these pictures never reach quite so fine a point of minute specialization
as do the best of those worn by birds and butterflies, for water obstructs
sight as air does not, and the eyes of subaquatic creatures are probably cruder
(?) organs than those of the higher land animals. Nevertheless, it is evident
that the predaceous fishes and other subaquatic animals see keenly, after a
fashion, and also that this fashion is not so widely different from our own,
because in all cases where we are able to compare the pattern of a highly
marked subaquatic creature with that of its natural environment, we find a
beautifully true and finely detailed correspondence between the two. From
these accessible cases alone one might plausibly infer that all highly patterned
fishes wear real background-pictures. But to a person with artistic sight
(i. e., sight highly and truly and roundedly developed), and an understanding
of obliterative coloration, a glance at any such fish far removed from its home
will leave no doubt on that score, even though the exact nature of the fish’s
normal environment remains unknown. Perhaps the most familiar among
the ‘ground’-haunting fishes that are not quite inaccessible to our study
in their homes are some of the flat-fishes—flounders, plaice, etc.—those queer
creatures that have departed so monstrously from the main piscine type.
Their wonderful protective coloration has long been a matter of common
remark; but here as elsewhere the subtle basic principle has been overlooked.
Flounders and their kindred, using one broad side as a back and the other
as a ‘bottom,’ are indeed very nearly ‘flat,’ and their exposed upper side
arches but little above the surface of the sand- or pebble-bed on which they
rest. But a close examination shows that this ‘back’s’ very slight convex-
ity is exactly compensated by a delicate obliterative shading, accelerated to
cope with the sharp rotundity of the back’s edges, and, downward, culminating
164

in the uniform whiteness of the flat underside—which serves the usual function
of shadow-neutralizing when the fish swims about. The upper side, as is
well known, is not only exactly like the sand or pebbles in general tint, but
is finely peppered with: lighter and darker, grayer and browner, flecks, in
exquisite imitation of the surface of the sand bed; or it is marked with va-
riegated pebble-patterns, or with the two kinds in combination, or with sea-
weed colors and patterns,—as the case may be.* The sand-picturing patterns
of these flat-fish are almost exactly duplicated by those of certain beach-
haunting amphibious crabs. Such for instance is the exquisitely dainty and
elusive little “Spirit Crab” of the American tropical and subtropical coasts.
This little crab dwells in myriads on the flat sandy beaches of the West In-
dian Islands, etc.; but its obliterative shading, sand-color, and sand-picturing
pattern are so potent that it is next to impossible to see it until it moves. Even
then it is inconspicuous enough, though it runs with great speed. Aquatic
crabs which haunt submerged rocks are marked much like the fishes inhab-
iting like situations. Those of northern seas are as a rule not gaudily colored,
although often richly marbled and spotted and streaked with accurate rock-
picturing patterns, founded always on full obliterative shading. Some of
these rock-patterns, particularly those of fishes, are almost as minutely accu-
rate as those worn by certain warm-blooded land creatures, such as the
Nighthawk (Chapter V, Figs. 30-31). As the Nighthawk’s pattern contains
an admixture of the picturing of lichens and other small and delicate dry-
land vegetable forms, so the rock-surface patterns worn by fishes contain
generalized pictures of seaweed, minute mollusca, etc.,—as it were the rock
lichens of the water. But whereas in cold and temperate seas this superficial
growth is comparatively scanty, often allowing the actual surface of the rock
to show, in tropical waters it tends toward a completely masking luxuriance
and ornateness. Particularly is this the case in coral regions. The fishes of
tropical coral-shores and reefs are almost as famous as tropical butterflies

* The rays (Radide) have much the same general system of coloration as the flat-fishes, though
usually wanting the minute adaptive markings.

165

for gorgeous brilliancy of coloration and variety of pattern. This gaudiness
of tropical fishes, so far from being, as most people have supposed, a mere
lavish expenditure of ornamentation, on Nature’s part, is merely one more
beautiful evidence of universally perfected obliterative coloration. As the
sunlit crown of the tropical forest is full of gaudy colors, so, and more so, is
the sunlit upper region of tropical ocean water, about coralline and rocky
shores and reefs, and white sand beds. What could be more natural and
appropriate than that the fishes living in such places should have, in addi-
tion to their never-failing obliterative gradation of general shades, intensely
brilliant colors, in rich and varied patterns? All the ‘paradisaic’ tropical
fishes, which have so often been marveled at, are in fact merely covered
with average-background-pictures, working for their wearers’ concealment
as truly as do the dull-colored and delicate patterns of the flounders and
northern rock fishes and rock crabs. To be sure, the background-pictures
worn by these ‘submarine butterflies’ are as a rule very much generalized,
for there is redundant variation in their surroundings, and some of them are
restless vagrants,—though seldom going far from the rocks or coral-beds.
Doubtless there are many kinds that ‘‘lie close,” and never wander far,—and,
accordingly, are equipped with more minute and definite pictures of gay cor-
alline and weedy backgrounds. But here our knowledge (i. e., that of the
present writers) is defective. Nevertheless, the kinds and degrees of oblit-
erative color- and pattern-adaptation among tropical fishes, even as we know
them, are many and various—too many and too various to be described in
detail here. A few more very general statements about them must suffice.
Their colors (besides black and white, and all the mixed tints of gray and brown
and olive) include the entire range of the spectrum,—red, yellow, blue and
green being perhaps the commonest, among pure colors. These, of course,
are the colors of coral, seaweeds, mollusks and other lowly marine animals,
and of water over sand and stones,—or, in other words, colors typical of the
fishes’ environments in fertile tropical seas. The above-named tints, with
very many more, occur on the fishes in all sorts of striped, banded, spotted
166

and blotched patterns, whose effect is ‘secant,’ ‘ruptive,’ or purely and del-
icately background-picturing, as the case may be. Iridescent or highly change-
able color is not so characteristic of these gaudy ground-haunting fishes as it
is of the free-swimmers that spend much time very near the surface. Indeed,
their brightest colors are often almost lusterless—like those of toucans and
parrots rather than those of hummingbirds and peacocks. This, also, is in
evident harmony with their ways and places of life. For, down in ocean
water, below all the surface-agitations, the light is constant and somewhat
diffuse, and plays few tricks of any sort; hence strong ‘dead’ color, in fit
background-patterns, is all that is required to complete the concealment of
obliteratively shaded fishes when they lie motionless in that quiet realm.
Some of the most elaborate and beautiful of the obliterative patterns worn by
such fishes are on the fins, particularly the dorsal and the caudal. When the
fins are extraordinarily long but unmarked, as for instance in the genus Cheto-
don, they sometimes bear a direct mimetic resemblance to blades of seaweed.
Mimetic in a similar way are also, probably, some of the tentacular excres-
cences of fishes—such as those of the “Angler” or “Hunting Frog” (Lophius
piscatorius, etc.). Indeed, the whole lumpy form of this sluggardly “angler”
suggests mimicry of a weed-grown rock or lump of coral, and its obliterative
shading is, I believe, scanty or wanting. There may, indeed, be a good
many cases of true mimicry among the fishes of grotesquely distorted form;
but we have no definite knowledge of more than one or two. On the other
hand, it seems that most of their excrescences and lengthened, ‘painted’
fins are, like the corresponding developments of birds, truly obliterative, and
codperant with full counter shading. The two uses however, are of course
constantly intervolved. Some of the pipe-fishes, and other .snake-shaped
haunters of floating seaweed, probably bear a mimetic resemblance to flat
weed-blades. But being themselves cylindrical, they cannot look flat without
the aid of obliterative shading, which, accordingly, is here used for the attain-
ment of a mimetic effect. (This is a common occurrence among lepidopter-
ous larve, as we shall show in a later chapter.)
167

In addition to all the wonderful devices of fixed adaptive color and pattern
worn by fishes, they have often the extraordinary gift of ‘chameleonism,’
i. e., quick, sometimes instantaneous, color-change. Indeed, some of them
have this power in a higher degree than any other vertebrate animals known
to man, their coloration being as it were ‘alive,’ and ‘fluid’—darkening
and brightening, and shifting its pattern, in swift, repeated mutation. Some-
times the changes are evoked only, or chiefly, by changes in the light which
strikes the fish’s surface. But no doubt the chief use of such changeableness
of coloration, in most cases, is adaptability to various backgrounds. The
fishes most subject to such ‘chameleonism’ are the gay-colored ‘ground-
haunters’ of tropical seas,—the very ones that are notable for their lack of
iridescence ;—but trout and probably other fresh-water fishes are also some-
what ‘chameleonic.? Mr. A. R. Dugmore, in his admirable and delightful
book on Nature photography (‘‘Nature and the Camera’’), gives some inter-
esting testimony on the subject. He, moreover, fully and clearly states the
fact that even the gaudiest tropical fishes are colored for concealment. But,
like all the rest, he ignores the great basic principle of obliterative counter
shading, without whose aid the color adaptation would be of so little avail.

So far we have considered mainly the fishes of salt water. But of course
the same general principles, with various small modifications, apply to fresh-
water fishes—the inhabitants of lakes and brooks and rivers. Some of those
I have already mentioned, such as the salmon and the herring, live in both
kinds of water, making annual migrations from the one to the other and back
again. These are all of the free-swimming type—with colors and markings
not specialized to match any one sort of ground, but rather adapted for gen-
eralized water-picturing near the surface. This, the type of coloration of the
generality of free-swimming “pelagic” fishes, is also, with modifications, that
of the free-swimming fresh-water kinds—much more localized in habitat
though they almost always are. Inland ‘bottom-fish,’ also, are much like
marine ones, though with less variety of coloration. Some of them are ‘mud-
fishes,’ and colored muddy brown or gray, with full obliterative shading,

168

but usually with scanty markings. Soft, dull mud, more or less barren of
vegetable or stationary animal life, and free from stones and sand, is a char-
acteristic fresh-water product. Such fish as the American Hornpout (Ami-
urus catus, etc.) haunt this simple element, and have a correspondingly plain
and simple obliterative equipment. So do the fish-like young of many frogs
and toads and salamanders—the “tadpoles,” in other words. But, as in
almost all other cases, there are gradations from this type of coloration into
others. The common American Brook Trout (Salvelinus fontinalis) varies
much in coloration, having even, as I have already mentioned, a ‘chamele-
onic’ power of almost instantaneously changing—lightening or darkening—
its general tint. The dullest-colored trout from a dark, muddy pond or brook
is only a few grades above the hornpout or the polliwog in fairness of tint
and elaborateness of pattern; while a light and bright one from a clear, shallow
stream is one of the most exquisitely and ‘specially’ marked and colored
of fishes. In the aspect of this fair trout’s common background there is a
characteristic which we have not yet considered, and which in its full display
is peculiar to shallow running water. That is, the system of moving light-
and-shadow patterns on the bottom, made by sun-rays variously refracted
from the agitations of the surface. Everybody is familiar with these beauti-
ful water-patterns, that glide and flicker over the beds of brooks in sunlight.
They are of many forms, as the surface-agitations are of many sorts; never-
theless one can distinguish a few predominant types among them. The sim-
plest consists of more or less nearly parallel and widely separated undulant
bright lines; the most complicated is a maze of twisting, branching, tremulous
bright bands encircling darker spaces—plaided, sometimes, like the scales
of a fish,—or like the giraffe’s pattern. These pretty effects are produced of
course both by wind- and current-ripples; but it is the currené-ripples that
make the greatest variety of patterns. Notable among these variations are
the whirlpool shadows. They are cleanly and perfectly circular dark spots,
each surrounded by a bright rim of sunlight. In all brooks whose passage
is in any way obstructed at the surface, little whirlpools are engendered here
169

and there, which glide down with the current till they flatten out and vanish.
When the sun shines, each of these little whirlpools as it glides along is ac-
companied on the bottom by its round, gold-rimmed shadow. Often these.
pretty spots may be seen trailing along in companies, and some stretches of
brook-bottom are always thickly speckled with them—appearing and gliding
forward and fading out in quick, ever-recurrent succession. Next to the
wavy, gold-laced ripple-patterns, this whirlpool-spotting is probably the most
universally characteristic element of the appearance of brook-bottoms in
sunlight. Nor are whirlpools the sole producers of this effect. Any little
pits in the surface of the water, such as are made by barely-floating specks
of débris, or by the lightly planted feet of water-skippers (H ydrobatide), cast
the same sort of gold-rimmed shadows, though seldom in such bright, con-
spicuous show. ‘These several so characteristic brook-bottom patterns might
be expected to occur in the background-pictures worn by brook-haunting
fishes. Nor have we to seek beyond the common American Brook Trout
(Salvelinus fontinalis) to find both wavy ripple-shadow patterns and circular
whirlpool-patterns in full application. The little, light-rimmed dark spots,
the familiar “trout spots,” are ‘painted’ on the fish’s side, above and below
the “lateral line,” and the wavy marks along the whole extent of his back
and on his dorsal fin.

There is much likeness to the ‘whirlpool’ spotting in the exquisite water-
patterns worn by certain seals (as, in some pelages, the Common Seal, Phoca
vitulina), which are also wholly fish-like in their smoothly graded obliterative
shading, and the general character of their coloration. But we do not know
enough about their habits and environment to say much about the special
functions of their markings. Other seals, again (i. e., the Bladder-nose,
Cystophora cristata), are marked, over full obliterative shading, almost ex-
actly like certain sea-fishes. ‘That is, they are irregularly dabbled and flecked
with black and white and gray, in what seems to be a generalized rocky (and
weedy?) bottom-pattern, as seen through several feet of water. Among fishes,
like patterns are worn for instance by some cod. There is certainly great sig-

170

nificance in this superficial likeness between animals so remote from one
another, fundamentally, as seals and fishes, which yet live much of the time
‘under common conditions, and have somewhat similar outward forms. Their
superficial resemblance is all the more notable in that the like colors and
patterns are produced in totally different ways in the two cases, those of the
fishes being in the skin, and those of the seals made with minute external
hairs. On the other hand, this is no more remarkable than the many familiar
cases of superficial resemblance among widely different /and animals which
have acquired kindred habits of life—e. g., some hummingbirds and hawk-
moths.

To sum up the main facts about the disguising-coloration of fishes,
as far as they are known to us: All ‘daylight’ kinds are obliteratively shaded,
with the possible exception of a few mimetic forms; while their particular
adaptive developments of color and pattern correspond to those of birds
and lizards and butterflies on land, and are almost—perhaps quite—as highly
and beautifully diversified. But about the exact nature of these special adap-
tive costume-developments of fishes, little is yet known. The subject’s very
inaccessibility lends it an exceptional fascination, and it must ultimately receive
the profound and detailed study it deserves.

171

CHAPTER XXIV
REPTILES AND AMPHIBIANS

AUDY and motley-colored almost as the brightest birds, butterflies, and
fishes, are some of the arboreal lizards and snakes of tropical forests.
The lizards are wonderfully light and agile climbers, wanting only wings * to
give them full command of the regions of airy outermost foliage, into which
they freely penetrate; while the most truly arboreal snakes are scarcely less
gifted acrobats, and spend much time in those realms of richest color. With
both snakes and lizards, green is the commonest color; but red, yellow, orange,
blue, etc., frequently occur on them, in various sharp ‘secant,’ ‘ruptive,’ or
generalized background-picturing patterns, exactly corresponding to those of
the birds inhabiting like regions, though differently modified to suit the lizard’s
and especially the snake’s very different bodily forms. The prevalence of
green in their costumes, also, is paralleled among birds, for, as we have seen,
the ‘lower tier tree-top birds’ of the tropics tend to be green; and the strictly
arboreal reptiles have almost the same local habitat.

Both snakes and lizards, and the bright-colored arboreal kinds as well as
those of duller tint and humbler situation, are almost without exception obliter-
atively shaded, to the full,f and this obliterative shading is almost wholly
essential to their concealment. As a snake has the simplest bodily form of
all vertebrate creatures, so is his obliterative shading, when complete, the

* A few kinds (the ‘‘dragons,” Dracho) have even parachute wings, like the flying squirrels.

+ Partial exceptions occur among the burrowing snakes and legless lizards, some of which have
almost monochrome surfaces, and among sea snakes. They, however, have obliterative shading in
gross, being dark above and light beneath, but with the two shades sharply contrasted instead of
connected by intermediate tones. In this they resemble certain whales. Whether or not all the
species of sea snake are colored thus crudely, I cannot say.

172

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‘ most beautifully simple to be found among vertebrates, not excepting fishes.
There can be no finer display of this great principle in full and pure applica-
tion than is furnished by the common green Grass Snake (Liopeltis vernalis)
of northeastern North America. (See Fig. 121.) Deep grass-green along the
upper median line, his color shades lighter by imperceptible gradations down
his sides, passing through pale straw-green along the edges of his ventral
surface, and culminating in dim greenish white on the flat underside. The
effect of this exquisite shade-gradation is to make the little snake appear of a
uniform, intangible, grassy green, when he lies at rest or glides along, on the
ground or in the bushes, in his normal position. Turn him over, so that his
pale belly is uppermost, and he becomes very conspicuous—looking grossly
solid (Fig. 122). He is still, on the whole, green, like his surroundings—
but by no means ‘obliterated.’ (!) In a normal position, ‘flattened out’
completely by the counter shading, the snake is not only likely to look merged
into his general green background of grass (or other vegetation), but, when
this illusion fails, and parts of his surface definitely catch the eye, they will as
a rule pass for portions of broad grass blades or flat leaf-surfaces. This is
mimicry, after a fashion, but it is mimicry achieved only with the aid of obliter-
ative shading—and the effect is decidedly of minor importance. Such im-
minglement of the two principles (‘obliteration’ and mimicry) occurs much
more pronouncedly among lepidopterous larve, which we shall describe in a
later chapter. In the case of the little green snake, the intrusion of the semi-
mimetic effect is due to his complete lack of markings. Any markings, super-
imposed on so perfect a counter shading, would almost infallibly look as if
they belonged to the background, thus clinching the obliteration. But simple,
immaculate coloration, with full obliterative shading, is very common among
snakes. In fact, it is about the commonest, as it is the simplest, type of ophid-
ian coloration, both among terrestrial and arboreal species. Most of the
snakes thus colored are swift and active kinds that seek and chase their prey
instead of lying in wait for it. The gliding motion of their long, slim bodies
would often be revealed by markings, in cases where without them it might pass

173

unnoticed. This is true especially of transverse marks. Lengthwise marks, as
has been explained in an earlier chapter, are much less conspicuous on a moving
object than those in any degree transverse. Stripes running the whole length
of the body, such as are worn by certain snakes, add nothing to the conspicuous-
ness of motion,* and in fact tend to lessen it, inasmuch as they split their
wearers’ forms, so to speak, into narrow, parallel lines of different colors or
shades, some of which are likely to match the moving reptiles’ backgrounds.
Markings of this kind also, are, I believe, almost wholly confined to swift hunt-
ing-snakes. On the other hand, although some snakes by no means sluggish
are transversely ringed (e. g., some of the coral snakes), yet markings of this type
characteristically belong to species which spend most of their time at rest, and
often or habitually lie in wait for their prey. Such markings, indeed, are as
particularly well fitted to conceal a motionless snake as they are ill fitted to lessen
the conspicuousness of one in motion. For, aided by background-marks of like
aspect and direction, they ‘cut up’ the motionless snake’s long form into short,
un-snake-like segments. Lengthwise stripes, under the same conditions, have
merely the effect of ‘splitting’ their wearer’s form into several narrow but snake-
like parts. So also many of the lizards that persistently “lie close” have bold,
‘transversely ‘secant’ bands. Such are most of the iguanas, and a great many
smaller species, both arboreal and terrestrial. Even the ‘oilcloth’-plaided
pattern of the sluggish Gila Monster (Helodermaia) is transverse rather than
longitudinal. More or less transverse also, though minutely varied and elabo-
rated, are the beautiful and terribly effective ground-picturing patterns of
such sedentary poisonous snakes as the Rattlers and the Copperhead (Cro-
talus and Trigonocephalus). (See Fig. 123.) ‘The Copperhead’s pattern is
especially remarkable. As the reader will see by looking at Plate XI, it pic-
tures with astounding accuracy heaped dead leaves, with their lights and
shadows. ‘This wonderful resemblance, like the rest, owes its power primarily
to the underlying or inwoven counter gradation of shades, whereby the snake’s
cylindrical solid form is visually ‘flattened out,’ and prepared for complete
* (i. e., of longitudinal motion)—A. H. T.

174

Fig. 121.

Vies, 121-122. Green
snake (Liopeltis ver-
nalis), right-side-up
(Fig. 121), and up-side-
down (ig. 122). (The
normally place d one—
Fig. 121—however, _ is
very poorly lighted for
‘obliteration’.)

Vie, 122,

¥1g. 128, The surroundings of this Rattlesnake have been made wholly by copying the snake’s own color-‘values,’— by perceiving what
y

scene he represents, and using
the stones he frequents.

each one of his ‘notes’ for the right detail of the scene. The result is an astonishingly true rendering of

This picture, like several others in the book, shows that animals’ normal environments may be exactly deciphered from their coloration

obliteration by means of background pictures. There are many other types of
ground-picturing pattern, more or less elaborately developed, among terrestrial
sedentary snakes. That of the loathsome and beautiful African Puff Adder
(Clotho arietans) is a good example of the desert type, which numbers many
species, both of snakes and lizards. The Puff Adder, and all of his kindred
which bear equally minute sand-pictures, are to the highest imaginable degree
fitted for “lying close’—more so, perhaps, even than such a wonder as the
Copperhead. Lizards’ picture-patterns do not often reach quite such minute
finish, and this is in keeping with the fact that almost all lizards are quick and
agile. Most kinds, though they may “lie close,” are yet always ready to resort
to sudden and swift dashes in case of pressing danger; and they often catch their
prey by long leaps or even running chases. ‘The picture-patterns of lizards ac-
cordingly tend to be more generalized and crude than those of snakes, but there
are of course many exceptions on both sides. Some tree-bark patterns of
arboreal lizards, for instance, are perhaps as highly specialized as any snakes’
patterns. (See Fig. 124.) Lizards, furthermore, have in many cases the won-
derful power of sudden color-change, or ‘chameleonism,’ which is, I believe,
wholly wanting among snakes. This phenomenon, mentioned in the last chap-
ter, is too well known to need detailed comment here. Suffice it to say that the
various adaptive costumes which the lizards assume and doff are practically all
and always equipped with full obliterative shading, and often with highly-
wrought background-pictures. (See Appendix A.)

One more type of marking among snakes calls for especial mention. That
is the sylvan sun-and-shadow or ‘leaf-checker’* pattern worn by some of the
big tree-boas and pythons. This type of pattern and its uses have already
been described at some length in Chapter XXI, in connection with leopards,
giraffes, etc. On snakes its form is somewhat different, as the reader will see
by an examination of the bits of boa pattern shown in Fig. 120, but the general
effect is much the same. Indeed, the resemblance in pattern between some of
these bits of boa and some of ocelot (Fig. 120), is close.

* (and hole-picturing)—A. H. T.

175

Mimicry, in the sense of the counterfeiting of single inanimate things, seems
to play but a very small part in the coloration of snakes and lizards, whose
disguising costumes are almost always obliterative, purely and simply. In fact,
we do not know any positive cases of such mimetic equipment among reptiles,
beyond the fragmentary sort mentioned in connection with the Green Snake.

Crocodilians—that is to say, crocodiles, alligators, and gavials—have not
very highly specialized protective coloration. Mud-colored, armored, and
unmarked,—comparatively speaking—they yet have counter shading, which
tends to ‘obliterate’ them, in the water and on land. Often, however, they are
so placed as not to be ‘obliterated,’ but plainly to show their great, hulking
forms. Then their irregular, lumpy outlines often serve to make them pass
for logs or stones. Unquestionably, they often present, either wholly or in
part, a mimetic resemblance to such objects. An alligator swimming or rest-
ing at the surface shows above water only his snout, his eyes, and sometimes a
portion of his back—three or four gray-brown lumps which look, to any but the
most experienced eye, like points of rock, or projections of a submerged log—
or cypress “‘knees.”” However casual, all such resemblances must be of service
to the alligator.* Such an animal’s more or less mimetic likeness to his inani-
mate surroundings is often increased by the sticking to his heavy, muddy back
and sides, when they are out of water, of bits of vegetable rubbish. This is
the case also with some of the great fresh-water tortoises, whose concealing-
coloration is at least as simple as the crocodilians. These tortoises even have
alge and various mosslike, lowly water-plants growing on their shells, and
some have dermal appendages which look like such plant-growths. For the
rest, they are obliteratively shaded, and more or less mud-colored. The gigan-
tic land tortoises, such as those of the Galapagos Islands, have even less to
show in the way of protective coloration. With no obliterative shading worth
mentioning, and no markings, they wear, it would seem, merely the simple,
organic colors of old, weather-beaten shells and wrinkled hides. Fruit-

* In furtherance of offensive operations. For the brutes are the kings of the waters they inhabit,
and have—at least when they are full grown—scarcely any predaceous enemies.

176

eating, huge, slow, mild, and immune from enemies, they have, apparently,
little need of adaptive coloration of any sort. The sea turtles, some of them
of almost equally great size, have decided obliterative shading, and some-
timies—particularly on their upper shell or “carapace”—obliterative pat-
terns. The Hawksbill (‘‘tortoise-shell”) Turtle (Eretmochelys imbricata),
for instance, has, as everyone knows, a beautifully marbled carapace. This
pattern is obliterative, being, no doubt, a generalized sea-ground-picturing
pattern, like that of many fishes, crabs, etc. Kindred patterns of the cara-
pace are worn by certain small fresh-water and land tortoises—such as the
“box turtle” (Cistudo carolina), of eastern North America: Two small fresh-
water tortoises of the same region are particularly notable for bright color
and clear pattern, namely, the common “mud turtle” or Painted Tortoise
(Chrysemys picta), and the little -yellow-spotted brook tortoise (Clemmys
guttata). The Painted Tortoise has complete obliterative shading of shell,
head, legs, and tail, and, in addition, beautiful obliterative markings on almost
all his exposed skin, and on his carapace, especially along its edge. Those
on the top of the blackish carapace are olive green, and narrow—mere ‘mar-
-ginal bands,’ bordering the plates—the rest are red and yellow, in the forms
of spots and broad streaks, on a dusky ground. These brighter markings
look like bits of rich-colored water weeds, above or below the surface, like
certain water and marsh flowers, like sun-flecks on the muddy bottom, and
like various other common details of pond and stream scenes. (Compare the
bill-colors of the Wood Duck, described and pictured in Chapter XI.) In
conjunction with the obliterative shading, and the general effect of dark water
and mud-color achieved by the head, legs, tails, etc., on which they occur,
these bright markings must often admirably serve as obliterative picture-pat-
terns. The under-shell or “‘plastron”’ of this turtle is immaculate light yellow-
buff, while a connecting shade between it and the dusky carapace is furnished
by the red-marked side-band of shell, and the similarly colored down-turned
edge of the carapace itself. The little brook tortoise (Clemmys guttata) has
the same general type of coloration, with many minor differences. Its bright

177

markings are all yellow, and mainly in the form of smallish circular spots,
which are scattered over the whole black carapace as well as over the fleshy
parts. On the head and neck and fore-legs some of them are lengthened out
into streaks. The plastron is buff-colored, but marked with big, irregular black
blotches—a pattern and coloration highly characteristic of the small American
tortoises. The obliterative effect of the circular bright-yellow spots is much
the same as that of the Painted Tortoise’s richer pattern; but the little yellow
disks are more aptly suggestive of spots of sunlight on dim brook-bottoms.

To sum up the foregoing fragmentary account of chelonian coloration:
Most turtles, aquatic and terrestrial, are obliteratively shaded, and, in a gen-
eral way, obliteratively colored; but comparatively few of them have highly
specialized obliterative picture-patterns.

We now come to Amphibians, the last of the vertebrate classes we have
to consider. These, unlike tortoises, are for the most part soft, weak-skinned
animals, living much exposed to danger, and being much preyed on by ra-
pacious creatures. Accordingly, their disguising coloration has been highly
and variously developed. Most variously, indeed, as their habits are ex-
tremely various; yet the principles we have already studied cover all the vari-
ations. In their larval state, as “‘polliwogs,” ‘‘tadpoles,”’ etc., these animals
are all more or less fish-like, both in habits and appearance, and their oblit-
erative coloration does not then differ essentially from that of certain mud
fishes (Chapter XXIII, p. 169). But in the perfect state the various types
become highly differentiated both from other animals and from one another.
How many and diverse, for instance, especially as regards disguising-colora-
tion, are the types of frog and toad! Even if we confine ourselves to those
of temperate North America and Europe (as we, personally, are obliged to
do, because of our ignorance of the no doubt far more diversely specialized
tropical forms), the essentially different types are many. First, there are
the aquatic frogs, as the common Green Frog and the great Bullfrog of North
America (Rana clamitans and R. catesbiana), etc. Then the terrestrial wood-
land frogs (Rana sylvatica, etc.), colored like some delicate forest ground-

178

bird; then the semi-terrestrial grass-haunting frogs (Rana palustris, Rana
virescens, etc.). Then, again, the terrestrial toads, aquatic only during the
breeding season, and otherwise fitted for life on and under comparatively
dry and open ground; then the little, tight-folding tree toads (Hyla, etc.),
modified both in form and color for concealment on perpendicular reed-stems,
on sticks and twigs, or on tree trunks and on rocks, as the case may be. The
Common Tree Toad (Hyla versicolor) of eastern North America, is a good
type of this remarkable group. It is a tree-bark haunter, veritably moth-like
in the exquisite minuteness and accuracy of its tree-bark pattern, and gifted
in a high degree—as many amphibians are in less degrees—with ‘chame-
leonic’ powers of rapid color-change.

Different as are the various batrachian types above named, both in habits
and in superficial aspect, they all have much in common even in their color-
ation. For they are all obliteratively shaded, delicately and fully, and the
concealment of all of them depends primarily on this same great principle.
Those which cling to tree trunks are, of course, lighted as are woodpeckers and
other scansorial birds (Chapter VIII)—that is, almost like the ground ani-
mals—and hence are similarly counter shaded. The little reed-toads and
twig-toads, folded up tight and smooth and narrow, and clinging close to
the tree-branch or reed-stem, are likewise ‘blended into’ the surface of their
perch by aid of their obliterative shading. But of course this is the case
only when they are seen in back view. In profile, they may still be and often
are ‘obliterated,’ being indistinguishable from whatever forms their back-
ground; but their lack of markings (a trait characteristic of some kinds, par-
ticularly green ones) hinders this effect, and must often cause their contours,
thus relieving, to be visible. Here mimicry comes into play; for their bodies
are so modified in form, and held in such positions, as readily to pass for
mere slight excrescences of the plant-surfaces on which they are sitting. There
may even be species whose whole disguising equipment is thus mimetic,
to the exclusion of obliterative shading. But, with or without these
possible few exceptions, the protective coloration of batrachians is preém-

179

inently obliterative, like that of all the other vertebrate orders we have
considered.

Most beautiful and minute, as I have said, is the picturing of lichen-
flecked bark on the backs of the obliteratively shaded and ‘chameleonic’
tree toads—e. g., Hyla versicolor. Equally effective and more remarkable
is the picture-pattern of some grass-frogs. ‘This pattern is closely akin not
only to the grass-patterns of certain birds (see for instance the ptarmigan in
Fig. 41, Chapter VII), but to that worn by some ground-perching moths,
which will be described in a later chapter. It pictures dim, grassy ground-
shadow overlaced with crisscrossing bright-green grass blades. The picture,
moreover, is one of unusual deceptive power—as everybody will agree who
has tried to catch these frogs amidst luxuriant grasses. Though the species
is of course not wholly confined to such grassy spots, its coloration fits them
far more closely than it fits any other sort of ground. As is almost needless
to say, obliterative shading is here, as in all kindred cases, the basis of the
obliterative effect. The more aquatic and mud-haunting frogs have perhaps
less highly specialized, but doubtless perfectly adapted obliterative ccloration.
The greens and browns of shore-weeds, of still, stagnant water, of water re-
flecting the green shore, of mud and sticks and water-soaked dead leaves—
such are the prevailing colors of these frogs. These tints are arranged, more-
over, in a system of complete obliterative shading, culminating usually in
yellowish white on throat and belly. The independent patterns they form
are more or less obscurely-mottled, but adequately serve as generalized pic-
tures of the frogs’ rather various muddy and watery backgrounds. Dull
black shadow-color is an important factor in these patterns. But neither
water-shine flecks of the brighter sort, nor bright brook-bottom sun-flecks
occur in them, so far as I know. Somewhat more specialized, again, is the
picturing of the leafy forest floor on certain woodland frogs, such as the pretty
little Rana sylvatica, already mentioned. (See Figs. 125-126.) Small as
this frog is, he yet wears two or three fairly definite leaj-edge-against-shadow
pictures, on his delicate pearl-brown and dusky, obliteratively shaded

180

Fie. 124. Brown Lizard (Kentucky) on the trunk of an apple tree.
Photographed from life by George C. Embody.

Fie, 127, Common Garden Spider on its web. Obliter-
ative patterns and obscure gray head, with a glaucous

web-trail made to match it.

Photographed from life by Dr. R. W. Shufeldt.

Fies. 125-126. Brown
Wood-Frog among dead
leaves and pine needles.
Delicately-detailed_ leaf-
picturing pattern, based
on perfect countershad-
ing. (Notice the shadow-
picture on the frog’s
cheek below the eye,
bordered on its lower
side by a sharp light
streak, which in its turn
has a narrow inferior
dark border, and per-
fectly represents a leaf-
stem, pine needle, or
sharp leaf-edge, with its
shadow.

Photographed from life,

coat. Though he is partially aquatic, like all his kindred, his colors are more
particularly suited to the time when he is out of water, and when, no doubt,
he is in more danger of being snapped up by predators. On the other hand,
his coloration is to some extent ‘chameleonic,’ and interadaptable to various
environments.

The common ground toads (Bujo) are more nearly terrestrial than any
of the frogs we have considered; but even they spend the breeding season
in the water. Characteristically, however, through the greater part of their
waking life, these toads are inhabitants of ground where there is exposed earth
or sand; and their coloration seems most closely to fit such spots. But it is
also well suited to dead-leaf-strewn ground, or any other sort of brown, mi-
nutely mottled earth surface. Founded on full obliterative shading, their
richly and delicately speckled picture-patterns, of various browns and grays
and duskies,* nearly approach the minute specialization of those worn by
goatsuckers and other ground birds. By far more sluggish than the mud
frogs (at least during the day—for they are nocturnal), and allowing enemies
to approach more closely, these toads are equipped, as one would expect,
with more highly finished obliterative coloration. Their warts—what-
ever may be their other uses—are effective agents in the background-
picturing.

Cruder ‘ruptive’ patterns seem to be almost wholly wanting among batra-
chians,—or at least among the tailless batrachians of temperate North America
and Europe. ‘Secant’ patterns of various kinds occur among them (see
Chapter XIII, p. 78), but usually, or perhaps always, they are also definite
features of the picture pattern—looking like a grass-blade, or a stick, or a leaf-
edge, or a gleam on shiny mud.

The tailed amphibians—newts, salamanders, axolotls, sirens, mud-pup-
pies, etc.—are lowlier than frogs and loads, not only in their general make-up

* The common American toad (Bufo americanus) and the European ‘“Natterjack” toad (Bufo
calamiia) are good examples of this type. But not all ground toads are thus colored; witness the
Green toad (B. viridis) of continental Europe.

181

but in their disguising-coloration, which presents few or no new or particularly
noteworthy features. They are almost all obliteratively shaded, and wear
colors and markings which tend to make them invisible against their normal
backgrounds; but few of them show a very high development of special adaptive
coloration. Some terrestrial kinds, living in rotten logs and stumps and be-
neath dead leaves, are extremely gaudy—wearing much bright blue, green,
purple, or sometimes red. But if we learned more about their habits, we
should probably discover some remarkable protective use of these bright
colors. They are usually brightest on the tail—sometimes confined to it—
and this suggests that they may serve the salamanders in the same way that
the banded tails of pheasants, etc., evidently serve these birds (see Chapter
XVITI)—that is, as baits or targets, to make their enemies strike behind (when
they are running) and miss the vital parts. This supposition is in fact ex-
tremely plausible, inasmuch as the tails of such amphibians, like those of many
lizards, are easily detachable, at any point, and are often left writhing in the
grasp of enemies, while the vital fore-parts to which they belonged escape.
Other terrestrial salamanders are marked with brown and brownish red—
dead-leaf and rotten-wood tints—and with dusky shadow-tones, in lengthwise
‘secant’ stripes. Others have transversely secant markings, and some are
rather brightly pied with black and whitish, or yellow. Others, again,
are marked with neat, circular spots of yellow, on a black ground, like the
little tortoise described on page 177, but with the spots proportionately much
larger. We, personally, know too little about the habits of these various species
to speak with confidence about the special adaptive fitness of their markings.
The coloration of the aquatic species corresponds more or less closely to that
of fishes. Some have pronounced obliterative patterns, picturing mottled
pond-bottoms, etc.; but the disguising coloration of many of them is very
obscure.

We have now finished our skimming survey of vertebrates. ‘The remaining
three chapters will deal with crawling and flying invertebrate creatures.

182

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CHAPTER XXV
CATERPILLARS

HIS is an immensely interesting branch of the subject.* The existence
of most naked lepidopterous larve is singularly dependent on protective
coloration, owing to the fact that they are the favorite prey of many kinds of
birds, and, living exposed to view on leaves, are also incapable of rapid motion.
This universality of the extreme need of concealing coloration among hairless,
leaf-eating larve, and the enormous number of their species, whose many and
diverse food plants, feeding habits, sizes, and fundamental structural shapes
call for an almost equally great variety of devices for the achievement of their
protection, makes the study of them peculiarly fruitful, as well as intricate
and difficult. Indeed, the subject is so vast, that no one, even if he devoted
years exclusively to it, could hope to discover and appreciate more than a small
fraction of the whole number of diverse but equally fine and remarkable pro-
tective-coloration developments of the larve of a single wooded region.

In the plates which follow, we show merely the pick of a small collection of
paintings and sketches made during two autumns largely devoted to the study
of caterpillars (and spiders), chiefly in southwestern New Hampshire, U.S. A.
Few and imperfect though they are, they yet illustrate fairly well several princi-
ples which are of primary importance. We have confined ourselves almost
entirely to hairless larva, because highly specialized protective coloration
plays a much larger part among them than among the hairy ones. This is

* (Historically, it is especially noteworthy as being the branch in which Prof. Edward B. Poul-
ton, of Oxford University, made his independent and earlier partial discovery of the law of Oblit-
erative Shading. At the time, however, he did not realize that the law had a wide application, even
among lepidopterous larve, and his subsequent original investigations of protective coloration have
been largely in the field of mimicry. See, however, the quotation from Nature at the close of our
first chapter.)

183

most natural, as naked larve are far more acceptable to most insect-eating
birds, and the very hairy ones are to a large degree protected by their hairs
alone, and have much less need of deceptive coloration. (It should be noticed, :
however, that, whether by coincidence or not, certain hairy larve bear a strong
mimetic resemblance to details of their environment. Thus some of the furry,
white or yellowish grass-caterpillars look wonderfully like the fuzzy flower-
heads of the grass on which they feed, or of other species of grass sure to be
common in the same field.)

The same great fundamental principle of protective coloration, which is the
essential root of the matter in the case of the vertebrate orders we have been
considering, namely the principle of obliterative shading, holds, to a very large
extent, among lepidopterous larve. But here again we must sharply draw
the line between mimicry and obliterative coloration, because the former, which
has played so small a part in the orders we have already considered, is among
caterpillars both common and highly developed, almost outweighing in im-
portance the other principle, with which it is in many cases intricately com-
bined and interwoven. Muimicry, then, does not attempt to render a creature
invisible as an actual, well-defined object, but causes him to appear, either
wholly or in part, to be something else than what he really-is. The resem-
blance of edible or harmless to inedible or noxious creatures for defensive, and
to some degree the reverse for offensive purposes, constitutes one of the sim-
plest and most generally recognized forms of mimicry, and one to which
naturalists have given much attention. Another sort, more to our present
purpose, consists in the resemblance of the unobliterated forms of single crea-
tures to single well-defined details of their natural environment. This last
principle is sometimes, notably in the case of certain caterpillars, altered and
elaborated into what may be called compound mimicry. This consists in the
imitation, by the surface-aspect of a single creature or part of a creature, of
more than one absolute detail of the environment,—which details, owing to their
lack of an underlying obliterative shading, still appear to occupy exactly the
position of the actual creature. The principles of obliterative coloration, on

184

the other hand, work together to render the creature’s actual surface unrecog-
nizable as the surface of any object or objects of the immediate foreground,

; causing it to pass for an empty space through which the background 1s seen.

Not being entomologists, we know little or nothing about these larve from
the standpoint of nomenclature and scientific classification. We have taken
them as we found them, valued them according to our recognition of their
various devices of protective coloration, and classified them, for our own par-
ticular purpose, according to these devices. In most cases we do not know
more than one stage of a caterpillar, and it is possible or even probable that
younger (or older) stages of almost any one of our most interesting specimens
may be totally different. Our point has been merely to recognize wonderful
cases of protective coloration, and to take them as they stand, for what they
are worth. .

Beginning with the large green larvee, such as those of the Luna and Poly-
phemus moths, which are disguised purely and simply by counter shading
and background-color, aided by a slightly ‘mimetic’ system of leaf-vein
markings and leaf-edge contour, we will trace the gradation of types to the
caterpillars whose astoundingly effective disguises are purely mimetic. Such
for instance are the larger gray, green, and brown twig-mimicking Geometre.
These larve, being furnished with bodies whose general shape, color, minute
surface-formation, and markings are copied perfectly from the twigs among
which they feed,—some of them with forked heads which are exact fac-
similes of the buds at the tips of many of these twigs, and others with heads
which simulate the truncated ends of dead twigs,—complete the deception by
clinging to a stem or branch by the back pair of legs alone, and standing out stiff
and straight, absolutely motionless for minutes at a time. But true mimicry
in almost all its forms has already been largely and appreciatively studied and
described by several naturalists, and we shall therefore devote little more space
to it than is necessary to establish clearly in the reader’s mind its relation
to the other systems of protective coloration among caterpillars.

Class I. Simple obliterative shading and leaf-color, usually aided by leaf-

185

vein markings and leaf-like contour. This class includes most of the very large
green caterpillars, such as those of the Cecropia, Polyphemus, Luna and
Promethea moths, many of the Sphinxes, and, with modifications, the larva of
Basilona imperialis, etc. Most caterpillars protected by this counter shading
hang upside down, and are therefore, of course, dark on the belly and light on
the back, exactly the reverse of creatures which stand back-uppermost. (A few
larve—some Sphingide among the number—test on the upper sides of twigs,
and are counter shaded accordingly, from dark on the back to light on the
belly, exactly like birds and beasts.)

Plate XII, Fig. A, shows a Luna caterpillar in a natural position, a good
example of the full working of fully developed counter shading. By this
device the larva, hanging in proper position among leaves, is enabled to lack all
appearance of solidity, and to ‘melt’ perfectly into the general, indeterminate
green of the mass of foliage which surrounds it. In addition to this purely
obliterative device, the caterpillar is furnished with leaf-vein-like bands and
a leaf-edge-like back-contour, so that if the eye of an enemy happens to detect
its surface as that of a distinct object separate from the general green, the larva
may still, by virtue of its perfect flatness of tone, greatly aided by these leaf-like
markings, merely pass for a flat leaf, or part of such a leaf. Without these
markings to further the deception, and to distract the observer’s attention from
the larva’s surface-texture, this, closely though it resembles that of leaves, would
often betray the creature, by its slight peculiarities of appearance. These
markings bring in an element of mimicry, inasmuch as they help the larva,
when he is revealed as a definite object, to pass for a leaf or leaf-portion no more
distant than he actually is from the observer, rather than picturing the back-
ground upon him. This is proved by the back-contour, which seems to mimic
the wavy edge of a single, foreground leaf, with its serrations of full size, rather
than reduced by distance; and the vein markings also are in keeping with this
plan, being pronounced and large. Many, in fact nearly all, of our large green
caterpillars have this form of protective coloration, and the Luna is chosen
merely as one good type of the class. There are many fine examples of it

186

among Sphinx larve, which often have the leaf-vein markings exaggeratedly
developed. The Polyphemus caterpillar, which closely resembles the Luna,
largely lacks these markings, but has an even more leaf-like contour.* There
are few creatures in all nature better obliterated by shade-, color-, and pattern-
devices than are many of these large green caterpillars, which are doubtless
much sought after by certain birds, as for instance the Broad-winged Hawk
(Buteo platypterus). A human eye needs much training to be able often to
detect a Luna or Polyphemus caterpillar hanging amidst foliage. Fig. B shows
the same Luna caterpillar with the back uppermost, the reverse of the normal
position. It will be evident to any eyes that the creature thus placed, so that
the proper effect of its light-and-shade gradation is exactly and doubly thwarted,
is extremely conspicuous, and that neither its leaf-green color, nor its leaf-like
markings and contour, both so extremely useful when codperating with the
proper effect of the fundamental light-and-shade-effacing principle, can now
avail it. The creature is now staringly revealed as a fat green larva, light on
the back and dark with shadow below,—as even monochrome solid objects are
plainly revealed to the eye. Figs. C and D are two Sphinx-caterpillar pic-
tures exactly corresponding to those of the Luna, as will be seen. Fig. C
shows the larva im situ, Fig. D reversed. An interesting modification of this
scheme is found in the caterpillar of Basilona imperialis, the Imperial Walnut
Moth. Lacking distinct leaf-markings, it is furnished with scattered, long,
light-colored hairs, which, when it is seen from a slight distance, completely
blur its surface, and greatly help its rough but adequately ‘obliterated’ green
body to blend with the general green of its foliage-background.t+

* The red warts, with a pearly luster, of which we have made no mention, and which are com-
mon to both species, are larger and brighter in the Polyphemus. Whatever may be their other uses,
they lessen the larva’s visibility, inasmuch as the tiny spots of gleaming light upon their tips suggest
to the eye the glinting of light through holes in the leaves. The huge and gorgeous warts of the
Cecropia caterpillar are not lustrous, and cannot serve this purpose, but they closely resemble dis-
ease-excrescences upon leaves, and may well be strictly disguising devices. Or they may be also
fixed defensive weapons, serving to make the larva unpalatable, as the branching bristles of the
Automeris io caterpillar certainly serve to make it dangerous, to a would-be devourer.

+ With us these caterpillars feed chiefly on red maple and white pine, and those of the bluish

187

Class II. Counter-shaded Leaj-edge Caterpillars. The members of this
class are protected by an exquisitely delicate codperation of obliterative shad-
img with minutely accurate flat-surface mimicry, and this system is variously
modified in different branches of the class. But this new principle must be
more exactly defined. By codperation of mimicry with obliterative shading,
we mean a resultant mimetic resemblance achieved throughout on a basis of
counter shading. Whereas pure mimicry is a matter of the actual form and
surface-coloration of animals, irrespective of any artifice of light-and-shade,
the mimetic resemblance to a flat leaf-edge in the case of these larve is achieved
by the aid of a delicate system of counter shading. That is, the elaborate single-
leaf pattern worn by them looks perfect only when they are so lighted as to bring
their whole counter-shaded body to an appearance of perfect flatness; or in
other words, their superadded pattern as well as their general surface-color is
obliteratively shaded to counteract the effects of the normal high-light and
shadow. ‘The markings are lighter, brighter, and sharper in proportion as
they are situated on parts of the creature which are normally more averted
from the light, and vice versa. (The oak-leaf larva shown in Fig. N is a good
example of pure and simple leaf mimicry, as opposed to leaf mimicry dependent
on counter shading.) 'Thiscomposite scheme might seem to belong rather to
obliterative coloration than to mimicry, but we must call it a form of mimicry,
for the reason that the resultant resemblance is to part of a definite object

green pine foliage are almost always of a much more bluish green than those which feed on
maple.

Another interesting example of pigmentation perhaps directly affected by diet is that of the
change from green to red undergone by many of the large caterpillars in the autumn, shortly before
their transformation into chrysalids, and at precisely the season when many of their food-leaves are
turning red. Not only the spinning-caterpillars, such as the Luna and Polyphemus, but also certain
of the sikless ones, notably the Basilona imperialis just mentioned, often turn tawny, reddish, or
almost bright red, or become strongly tinged with such colors, shortly before they stop feeding, in the
late summer or autumn, when they have attained their full size. Thus it cannot be merely a matter
of silk-development in their bodies; and it is further noteworthy that the specimens of B. imperialis
which develop on pine or spruce trees (spruce is occasionally eaten) rarely or never turn wholly red,
while their neighbors of the maple trees are often of a rich copper color, or even brighter, when they
descend the trunks to enter the earth.

188

EXPLANATION OF PLATE XIII

Fic. E. LARGER-SPOTTED ~° FigiF, SMALLER-SPOTTED
. BEECH-LEAF-EDGE CATERPIL- BEECH-LEAF-EDGE CATERPIL-
LAR IN POSITION, passing for a part LAR IN POSITION. Cf. Fig. E.

‘of the leaf on which it is feeding.

Fig. H. SMALLER-SPOTTED
' BEECH-LEAF-EDGE CATERPIL-
LAB, DETACHED, INVERTED.

“Fie. G. LARGER-SPOTTED
BEECH-LEAF-EDGE CATERPIL-
LAR, DETACHED, INVERTED. *’’ -

Fia. I. WHITE-BIRCH-LEAF- Fic. J. WHITE-BIRCH-LEAF-
EDGE CATER@ILLAR IN POSI- . : EDGE CATERPILLAR, DETACHED,
TION, passing for a continuation of BACK-VIEW. Cf. Figs. E—H.

the leaf on which it is feeding.

* Fig. L. . dA : :
Fie. K. JAGGED-LEAF-EDGE’ Pa ey & — 2 poe
(ELM?) CATERPILLAR IN’ POSI- ip ee LAH ”

TION.

direct sky-light making leaves and
caterpillar bluer. )

Figs. E, F, G, H, and K, painted from life by Gerald H. Thayer; Figs. | and J by A, H. Thayer (Leaves, E.:B. T );
Fig. L. by Louis A. Fuertes

1h.
fod sage

PLATE Xill

AWOEN &CO BALTIMORE |

in the actual position of the counter-shaded creature, rather than to its back-
ground. With this explanation we can proceed to a more particular de-
scription of these wonderful larve. They feed, and, unlike most caterpillars,
rest, on the edges of leaves, and as their weight always draws downward the
edge to which they are clinging, they are to some degree caterpillars of the up-
side-down habit, and accordingly must have, in order that their appearance of
solidity shall be effaced, an inverted obliterative gradation of light-and-shade.
Unlike the larger counter-shaded caterpillars, such as the Luna, which cling to
stems far in among the foliage, they are usually fully exposed to view, on the
edges of outside leaves, and hence it is imperative that their surface, perfectly
flattened in appearance, should imitate as closely as possible the leaf-texture.
The degree to which this is achieved is one of the most exquisite and wonder-
ful things in the whole field of protective coloration. No caterpillar is harder
to detect, at the closest range, than is one of these beautiful leaf-edge larve in
its natural position. The minute reticulate markings of the healthy leaf-
surface are closely copied on the larva’s counter-shaded body by small dark
flecks, and, in addition, he often wears facsimile pictures (rendered perfect
by the same process of counter shading) of leaf-disease-spots. These spots,
and even the general coloring, vary somewhat in size and shape, but always
within limits beyond which the disguise would begin to be impaired. We
have seen many such caterpillars, representing several species and probably
several mere varieties. As a rule, it seems to be true that one kind of tree
harbors only one kind of ‘leaf-edge’ larva, which is almost or quite peculiar to
it, and rarely to be found on any otherplant. In the case of the beech, however,
which feeds a greater variety of particularly interesting ‘ disguised ’ larve than
any other tree we know, we have found three quite distinct species of the leaf-edge
class infesting it, and one of them, whose coloration is less distinctive than that
of most, is pretty often found on other trees. Again, the form inhabiting
certain kinds of maple, and wearing the deep-red spots of diseased maple trees,
occurs also on witch-hazel, and its spots are then usually browner and smaller.*
* Possibly we are here speaking of two species.

189

Plate XIII, Fig. E, shows the larger-spotted species of beech leaf-edge larva,
in its normal position. Fig. F shows the smaller-spotted species in position.
Figs. G and H show these two larve inverted, against a black background.
Figs. I and J are two sketches of a white-birch leaf-edge larva, I being the
creature im situ, and J a simple back view. Of this larva we have seen only
two specimens. It is but slightly shaded from dark to light, and either lives
usually very far in among the leaves, where the light is diffuse, or else, because
it feeds on rather stiff leaves, whose edges are but slightly pulled downward
by its weight, can make little use of counter shading. The light spots on this
caterpillar closely picture the small, transparent worm-scars so common on
the leaves of the white birch.

As we have said, the principles involved in the protective coloration of
this group of caterpillars are variously modified. The forms just described
are among the commonest and most noteworthy of those we have seen, but they
lack one element of finish which is found in caterpillars of another branch of
the class. Those already described have backs very slightly indented be-
tween the segments, and without humps, hence their contour can never pass
for the perfect edge of a leaf which is in any degree serrated, as most leaves are.
But as they freely mow away whole sides of leaves, and usually rest close to the
stem on the mutilated edge, this is hardly a lack. They merely pass for a con-
tinuation of a gnawed and imperfect leaf-edge, in whatever position they cling,
except in cases where they are so far from the stem that their backs are
farther out than even the unbroken leaf-edge could be—as sometimes when
they are beginning a new leaf. In such a case the smooth back-line is, momen-
tarily, a defect. (This need hardly be taken into account, however, because
it is the habit of these larve to work in along the midrib of a leaf, from a
position on the stem, and it is only in rare cases that their backs are out beyond
the line of a normal leaf-edge.) The caterpillars of the other type, of which
we have as yet seen only one individual, may be called the contour leaf-edge
larvee, for their back-contour is formed in close imitation of the perfect, serrated
edges of the leaves on which they feed. This resemblance is effected by a

190

series of high, double-pointed humps, one on each segment back of the front
feet, and is further aided by certain markings between and on these humps.
Such a caterpillar, therefore, doubtless tends to keep itself adjusted so that
the line of its back continues that of the unbroken leaf-edge, from each side of
the hole it has gnawed, and in which it is resting. It is also furnished with
diagonal darkish lines, one on each segment, which closely resemble the parallel
vein-markings on such leaves as elm and birch. Our specimen had no disease-
spot representations. The gradation from dark to light (dark on the belly
and light on the back, of course, because this is one of the upside-down cater-
pillars) is perfect, and the larva’s invisibility of course depends primarily
on this, as the two figures (K and L) show. Unfortunately, our only specimen
was found on the ground, and we cannot be sure what its particular food
plant is. The fact that elms were common close about it, as well as its beau-
tiful resemblance to’ the edge of the small elm leaf on which we placed it,
make it seem likely that it belongs on this tree. This caterpillar may be said
to constitute a separate division of the counter-shaded leaf-edge class, which
division we may define as follows:

Class II, Division A. Involves all the principles assigned to Class II
(with the exception, as far as we know, of the leaf-disease-spot picturing), with
the additional element of leaf-contour mimicry achieved by humped segments,
and pronounced leaf-vein markings. (Fig. K shows the caterpillar in posi-
tion, Fig. L inverted.)

Class II, Division B. The protective coloration of these larve involves
the principles already assigned to Class II, coéperating with an additional
distinct element of background-picturing. We have here a new and very
wonderful departure from the simple leaf-edge types already described. The
caterpillar shown in Plate XIV, Fig. M, a strict leaf-edge inhabitant, is, down
to a certain point on its back, exquisitely counter shaded and colored to re-
semble the bluish-green upper surface of a beech leaf, its usual food. Its
body is even furnished with minute black specks, in apparent imitation of the
faintly marbled aspect of the leaf. But this graded green, fading into a pure-

191

white line along the sides of the back, terminates then abruptly against the
smooth, deep yellow green of the back itself. Thus it appears that the
perfect flat-leaf-edge color achieved by counter shading extends over part of
the larva, and then suddenly gives place to an entirely contradictory and at
first inexplicable stripe of dark, exactly where the culmination of paleness would
normally occur. Finding the larva on the ground, one may well be puzzled,
but the first sight of it normally situated on a leaf is a revelation, as our picture
(Fig. M, 1) shows. The counter-shaded blue-green belly and sides repre-
sent an extension of the upper side of the leaf, the white line is an intensified
representation of the line of the leaf-edge, and the sharply contrasted and
deeply shadowed yellow-green back simulates perfectly the shadowed under-
side of a leaf, either the same one or one slightly more distant. If we examine
the caterpillar very closely, we discover still another wonderful detail of its
disguise. The dark-green back itself is slightly counter shaded to escape all
trace of a solid appearance, and to match perfectly the monochrome under surface
of leaves. A narrow yellow line runs along the middle of the back, and this
serves to efface the culmination of shadow which would otherwise appear
there. In the case of this /eaj-edge larva the green back doubtless often passes
for the underside of the same leaf, as shown in the picture (Fig. M, 1),
but in that of certain larger caterpillars which wear a similar device, as for
instance the larva of the common smaller hog-nosed woodbine caterpillar, the
illusion is less exact; and as this caterpillar rests on a stem rather than a leaf-
edge, even its light patch often passes for a portion of some partially concealed
leaf, rather than for the continuation of a wholly exposed one.

The modifications and different adaptations of these various principles
are almost unlimited, and we can only hope to give examples of a very few
most highly representative and easily comprehensible forms. Fig. M gives
three representations of the beech larva just described, 1 being the larva in
position on the leaf-edge, 2 the same detached from the leaf, and 3 a simple
back-view of the creature. These caterpillars are usually unspotted, as here
shown, but are sometimes marked with brown patches closely resembling

192

EXPLANATION OF PLATE XIV

Fig. M. UNSPOTTED BENCH-LEAF-EDGE CATERPILLAR

1, In position, part of him passing for a continuation of the leaf on
which he is feeding, and part of him for the underside of the same leaf.

2, Larva detached from the leaf.

3. Ditto, ‘back-view.

Fic. N. OAK-LEAF-EDGE CATERPILLAR

ete eh

Detached.

Fics, O and P. OAK-LEAF-EDGE CATERPILLAR

Tn position.

; & ig. Q. CRUMPLED-AND-WITHERED-LEAF-EDGE-MIMICKING CATERPILLAR

In position, representing edge of diseased portion of leaf.

Aa Ow
otc: Ae
i
i
t

Painted from life by Gerald H. Thayer (Leaves, Figs. M. and Q., —.B. tT.)

PLATE XIV

AHOEN & CO BALTIMORE.

those common on beech leaves—much like the species shown in Fig. G. We
have also seen one or two wearing almost the same general scheme of pattern,
but done as to color wholly in brown,—and it happened that these were found
resting on twigs or stems, instead of leaf-edges.

Class III. Purely mimetic leaj-edge larve. Complete leaf-edge mimicry
without obliterative shading. The caterpillar shown in Figs. N, O, and P,
although strictly a leaf-edge larva, deviates so widely from one of the main
principles of that class as above defined that it must be treated separately. It
lacks, namely, all trace of obliterative shading, and its beautiful, shiny, oak-
leaf green, more closely like a leaf in surface-texture than is that of any of its.
relatives we know, is of one uniform shade and tint, so that the larva can never
escape the full appearance of a solid, cylindrical body. But the perfect leaf-
color and texture of its green parts, in codperation with the marvelously minute
counterfeit of the transparent, brownish worm-scars so common on oak leaves,
which the remainder of its body wears, make it—when, as is its wont, it hangs.
inverted from a leaf—pass for the down-curled edge of it. The vein-pattern
is minutely copied on the larva’s brown parts, and between the green
and the brown there is usually a narrow, irregular yellow line, exactly such as
the leaf commonly has. The broken-leaf-edge aspect is further aided by the
brown hump on the caterpillar’s fourth segment. Altogether, though lacking
light-and-shade gradation, this is one of the most wonderful of protectively
colored caterpillars, and one of the very hardest to detect im situ. We have
sometimes found this caterpillar on beech, the leaves of which have worm-
scars very like those of oaks.

Class III, Division A. (Fig. Q.) Structural and pattern mimicry of an
irregularly crumpled leaj-edge (thus approaching the scheme of the structur-
ally mimetic larva shown in Fig. S, though the latter is not a leaf-edge inhabi-
tant). This division includes un-counter-shaded leaf-edge caterpillars of a
different type from the oak larva—those, namely, which, by color, pattern,
and curiously humped backs, simulate the irregularly crumpled and withered
edge of a leaf. Their bodies are almost always crossed near the head by a

193

band of leaf-green, which greatly furthers the deception. There are many
wonderful caterpillars of this type, usually a good deal larger than the one
here shown, which is the only one we have succeeded in painting.

Class IV. Partial mimicry of a detail of the normal surroundings, with a
polished back which under certain conditions reflects the color of surrounding
objects, combined with flat-leaj-edge counterfeiting, achieved by light-and-shade
gradation. The pretty caterpillar shown in Plate XV, Fig. R (No. 1 reflecting
nothing, No. 2 reflecting ‘green, and No. 3 reflecting red), is our sole example
of this class. Its light, extremely shiny back, which serves for shadow-efface-
ment when the caterpillar hangs upside down, serves also for actual reflection
of the color of the encompassing foliage (as in the white spider shown in Plate
XVI, Figs. V-Y), while the yellow stripe down its side must usually pass for
the stem of some other poplar leaf than the one on which it is feeding. The
fact that this well-pictured stem must, owing to its large size, appear to be at
least as near the observer as the caterpillar actually is, allies the case to partial
mimicry rather than to simple obliterative coloration. When the caterpillar
rests on a yellow stem, rather than a leaf-edge, as it often does, the mimetic
element is still more pronounced, for then the stem which he is in fact conceal-
ing with his feet is by his yellow stripe made to appear to pass on uninter-
ruptedly, if somewhat crookedly, and the remainder of his body merely merges
with the general green which surrounds him. This larva we have found only
on small-leaved poplar trees.

Class V. Complete structural mimicry of a common detail of the creature’s
habitual inanimate surroundings. The wonderful little caterpillar which we
have chosen to typify this class bears on its back a double row of large fernlike
fronds, with perfectly developed stem and branches, and when feeding or
resting amidst the curled-up edges of unhealthy maple or other leaves, which
it-evidently mimics, is almost impossible to detect. In its elaborateness and
efficiency, this disguise is among the very most wonderful. At the season
when the caterpillar is to be found, most of the forest trees have many of these
partially withered leaves. Wherever the creature stands on a leaf, it passes

194

EXPLANATION OF PLATE XV

Fia. R. ‘MIRROR-BACK’ CATERPILLAR

Painted from life by Gerald H. Thayer.

‘1.
2. Reflecting leaf-green.
3. Reflecting a red leaf.

Fie. 8.
CRUMPLED-LEAF CATERPILLAR

Painted from life by G. H. Thayer.
(Leaf, Emma B, Thayer.)

1. In position, back-view.
2. Ditto, side-view. .
3. Detached, enlarged. '

Reflecting nothing (save the sky-light). €

Fie. T.
CURLED - DEAD - LEAF - MEMICK-
ING SPHINX CATERPILLAR, IN
POSITION.

Painted from life (larva and withered leaf) sy fvie
A. Fuertes. (Live ‘Teaves, G. H. T.)

PLATE XV

AMOEN & CO. BALTIMORE _

for a dead and crumpled spot. The specimen here shown had lost one of the
fronds from its right side. (These caterpillars are said to shed their fronds
and weave them into their cocoons.) (Fig. S, Nos. 1, 2 and 3.)

Class VI. Highly developed color-and-pattern mimicry, scarcely aided by
modifications of form, of a detail of the caterpillar’s usual inanimate surround-
ings (Fig. T.). The plants on which this late-developing sphinx larva
commonly feeds, bear, almost invariably, at that season, a few black dead
leaves, frost-bitten or otherwise wilted—and the caterpillar, hanging head
downward, is a close counterfeit of one of these. The imitation is very close
indeed,—even the usual dark hole at the bottom of such a leaf being rendered
by the black spot on the caterpillar’s head, intensified by the encircling white,*
and the vein-markings being accurately copied by diagonal stripes and fine
reticulations. The tail-horn, which this larva has in common with most
sphinx caterpillars, here serves to counterfeit a leaf-stem, the midrib continu-
ation of which through the leaf is closely imitated on the caterpillar by a pro-
nounced light line. ‘These markings and details of form are largely the same
as those found on obliteratively shaded sphinx larve, where they serve the
same general purpose of leaf-stem and vein imitation; but the present
case, being one of pure and simple mimicry, allows of a clearer and more
definite development of these details. Notice this caterpillar’s complete
lack of light-and-shade gradation. He is equipped, not to be unapparent
as a solid object, and to merge with the details of his average background,
but to appear to be another kind of definite, rotund body than such as he
really is.

Class VII. Compound mimicry of normal inanimate surroundings, coupled
with an element of background-picturing. (Plate XVI, Fig. U.) This cater-
pillar’s several light-colored longitudinal stripes resolve themselves into the
appearance of separate needles of the white pine tuft in which it feeds. But
the darker and broader green stripes (sometimes partly dark red) then pass
for the general background of needles, against which the light stripes show as

* See Chapter XX, p. 125; Chapter XXII, p. 157, and Fig. 120.
195

separate, glistening, nearer ones. Thus the scheme departs from true mimicry
and approaches obliterative coloration, as it has already departed from simple
mimicry by the fact of its simulating more than one absolute foreground object.
This is one of the uncommon and noteworthy cases where an element of oblitera-
tive coloration is present without obliterative shading. The caterpillar’s head
is marked with red and yellow, in close imitation of the scales at the bases of
the needles—and it usually rests with its head against or near these scales.
It is a kind of sphinx, and, as far as we know, it feeds exclusively
on pine. Indeed, its mimetic resemblance to pine needles has been com-
mented on by entomologists. Inthe picture, No.1 is a back view, No. 24
side view. vU

We have now, in the matter of caterpillars, reached the end of our material.
The forms mentioned and figured are, as has been said, only a very few out of
an enormous number. We ourselves have found many other equally note-
worthy ones, which for various reasons we have failed to figure. Among the
most interesting of those omitted is the caterpillar of one of the Lappet moths,
which achieves in a remarkable way very simple mimicry of a slight protub-
erance on a thick tree branch (the sort of perch on which it, unlike most cater-
pillars, is wont to rest). Its body is much flattened, and fits closely to the
branch; and it is marked, irrespective of the scattered hairs, in close imitation
of the bark. There is no light-and-shade gradation, and the shadowed sides
of the caterpillar, as well.as the shadowed crevice which would show between
it and the bark, are beautifully bridged over by an obliquely descending fringe
of numerous hairs. So slight is the larva’s actual surface-rotundity, indeed,
that under favorable conditions it doubtless seems to merge with the flat or
slightly rounded bark-surface; so that this is another caterpillar whose disguise
in part achieves ‘obliteration’ without counter shading.

We have at least figured and described enough widely diverse caterpillar
disguises to suggest the wonderful richness of this great field of study, still
almost unexplored. Anyone who will devote a few late summer and early
autumn days to caterpillar hunting, along wooded roadsides—finding them by

196

EXPLANATION OF PLATE XVI

Fic. U. PINE-TUFT CATERPILLAR

Painted from life by Gerald H, Thayer.

1. Back-view.
2. Side-view. °

Fies. V, W, X, Y, PORCELAIN-WHITE SPIDER

Painted from life by Gerald H. Thayer. (Leaves, E. B. T.)

Figs. X and Y, spider suffused with green light amid foliage.

PLATE XVI

AMOEN @ CO BALTIMORE

the aid of their droppings on the ground, and trying always to see them in their
natural positions—will not only soon be acquainted with many forms like
those we have described, but will, if he has the trained artistic sight with
which to recognize them, discover many new and equally wonderful
cases.

197

CHAPTER XXVI

A GLANCE AT INSECTS OTHER THAN LEPIDOPTERA (ORTHOPTERA, COLEOPTERA,
HYMENOPTERA, DIPTERA, ETC.), AND AT SPIDERS

ERE we should be totally overwhelmed by the hugeness of the subject,

and foiled by our own ignorance, if we sought to give more than the
slightest general sketch of the main prevailing principles. Passing by * the
wonderful purely mimetic developments, such as_ those occurring among
insects of the families Mantide and Phasmide (walking sticks, leaf insects,
mantises that mimic flowers, etc.), which have been studied and described by
many naturalists, and with many of which the world at large has long been
familiar, we will confine ourselves to a rapid survey of the mass of less
obviously remarkable types. Beginning with the three main families of
Orthoptera (grasshoppers, locusts, and crickets) we find obliterative shading
playing its usual important part, though in less uniformly high development
than among vertebrates. Ground-perching locusts (Acrydiide) are all (?)
obliteratively shaded, in full, and furnished with ground-picturing patterns,
some of which are almost as minutely finished as those of Nighthawks, desert
snakes, etc. Some kinds habitually perch on rocks, and have true and fine
rock-patterns, much like the Nighthawk’s. Others, again, resorting much
to sand, and bare, dry earth, have more sandy-peppered patterns, like that
of the Puff Adder. Somewhat more brightly colored, as a rule, are the
many species which habitually perch on or amidst terrestrial vegetation. They
are flecked and patched, banded and striped, with grass- and ground-weed
tints—green, yellowish, red, olive, brown, and black, in more or less general-
ized picture-patterns (or sometimes more crudely ‘ruptive’ ones). Lo-

* As we ignore, for the present, all questions of ‘live ’-mimicry among these insects.

198

custs, as a rule, “‘lie close,” sitting tightly folded; their fore-wings (which, with
the head, sides, and legs, bear the counter shading and fine patterns) wholly
hiding the broad, membraneous hind-wings. These are often brightly and
boldly colored, without minute patterns, and when expanded in flight, against
sun-variegated backgrounds, they lessen the conspicuousness of the moving
insect just as do the bold ‘ruptive’ markings of many butterflies (and moths).
(See Chapter XXVII.) Some of them, again, must under certain conditions
act as ‘dazzling’-marks, by their sudden display and equally abrupt eclipse.
Among the Locustide or true grasshoppers, some of the more terrestrial
kinds have much the same general system of protective coloration as have
the herbage-haunting Acrydiide above described. For the most part, how-
ever, even these terrestrial ones are less finely patterned, having mere simple
‘ruptive’ patches of green and brown, or kindred colors, and the bright-back-
ground picturing above mentioned plays but a small part with them. Many
of the more arboreal kinds—of which the well-known ‘“‘Katydid” (Platy-
phyllum concavum) of the eastern United States is a good example, and even
some of those that haunt terrestrial herbage, are disguised by leaf mimicry,
for the attainment of which the whole body seems to have been modified.
The pith of the resemblance, however, lies in the fore-wings, which, when
folded, largely or wholly (according to the species) inclose and hide the body,
and which, being of a perfect, bright leaf-green, are also marked with a leaf-
like midrib and netted side-veins, so that, in profile, the insect closely simu-
lates a narrow leaf, or portion of a leaf. But, as in the case of the leaf-edge
caterpillars described in the preceding chapter, this mimetic resemblance
is largély indebted to obliterative shading. Externally convex, and folded
downward over a more or less cylindrical body, these fore-wings are made
to look flat by a delicate counter shading, just as we have seen in the case of
the caterpillars’ bodies. When, as is the way with several species of leaf-
mimicking grasshoppers, the fore-wings are comparatively narrow, so that
much of the body is exposed, it is obliteratively shaded, to the full, and hence,
in the right position relative to the light, it too is ‘flattened,’ and continues

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the flat-leaf aspect of the wings. But the effect in this case is less strongly
mimetic, for the body presents a less leaf-like surface than the wings, especially
in its lack of venation. Indeed, some of the green grasshoppers have scarcely
more than a general obliterative equipment of counter shading and foliage-
color.

The next family of Orthoptera, the Grillide or crickets, have less to show
in the way of disguising-costumes. Mainly nocturnal, and in many cases
subterranean and fossorial, they largely lack highly developed colors and
patterns. Most of them are black, blackish, or brown,—monochrome, without
pronounced obliterative shading. Diurnal kinds, which stay above ground,
will doubtless all prove to be obliteratively shaded, though still dull-tinted,
—very few (or perhaps none) of them sharing the livelier coloration common
among their relatives the locusts and grasshoppers.

The cockroaches and earwigs (Blattide and Forficulide) are likewise
nocturnal—shy and seclusive haunters of dark holes—and their protective
coloration amounts, apparently, to little or nothing beyond a general dull,
earthy brownness of tint. ,

The Coleoptera, or beetles, in the adult state,* are, for the most part, tough,
hard, and shelly, and probably less welcome food, to the majority of insect-
eating animals, than are caterpillars, locusts and grasshoppers. Many of
them, moreover, are equipped with rank defensive (?) stenches, as well as with
strong biting jaws; and many are nocturnal—skulking by day under stones,
under rotten bark, or in other safe retreats. Considering beforehand all these
facts, we should not expect to find beetles, as a class, particularly well pro-
vided with disguising-costumes; and they certainly are less so than some of the
more ‘succulent’ tribes of insect. On the other hand, they are by no means im-
mune from enemies, nor do they, in the great majority of cases, lack oblitera-
tive coloration. Few have simple obliterative shading, as few have the regular
perching-habits, the habitual ‘same-side-up-ness,’ indispensable to the full

* Their larve almost all live hidden away from the daylight, and are as a rule monochrome
and patternless,—often colorless.

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operation of that disguise, but many are equipped with brilliant iridescent
or metallic colors—green, blue, purple, bronze-red, bronze-yellow, etc.—
which strongly tend to obliterate them amid and against vegetation. The
fact that some nocturnal and subterranean kinds as well have rather brilliant
metallic colors * merely reminds us how much is still to be learned about their
habits. But it is, as far as I know, among truly diurnal species that the highest
brilliancy of coloration occurs. Sometimes, as on certain tiger beetles (Cicinde-
lide), etc., brilliant iridescence is combined with small, dull, sheenless spots,
and the effect of this combination, in a proper view, is highly obliterative,
particularly if the beetle is also counter shaded. Or again, iridescent brilliance,
in spots or stripes, may be a small factor of a soberer pattern. Innumerable,
indeed, are the variations of generalized obliterative pattern—‘secant,’ ‘rup-
tive,’ etc., in bands, stripes, spots and mottlings—which occur among beetles.
Black, yellow-buff, reddish brown, and yellowish green are probably the
commonest colors of the bolder patterns, which are strongly obliterative
against most natural backgrounds, though by no means highly specialized.
Transverse ‘secant’ marks predominate in these patterns, in accordance with
the simple laws of ‘obliteration,’ already many times explained. But much
more subtile patterns also occur on the Coleoptera, especially among those
which habitually rest on the bark of trees in the daylight. Even on beetles, such
finely mottled and grizzled tree-bark patterns are usually accompanied by oblit-
erative shading, and hence are true ‘picture-patterns.’ If the counter shading
were absent, the disguise would be mimetic, making the beetle look like an ex-
crescence on the bark. But we do not know of any pronounced cases of this
kind. Some flower beetles also have full and delicate obliterative shading. Of
these the American Rose Chafer (Macrodactylus subpinosus) is a good example.

But for all their frequent obliterative patterns and rich, iridescent vegeta-
tion-colors, the Coleoptera, as a group, are far from taking top rank among
‘disguised’ animals, or even among disguised insects.

In the order Hemiptera there are relatively even fewer notable types of

* Most of them, however, are black or blackish.

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disguise. Cicadas (Cicadade) are among the largest and finest insects of
this group, and their disguising-coloration, in the case of some kinds at least,
is very elaborately wrought. The Common Dogday Cicada of eastern North
America is the species with which -we are most familiar, and it will suffice
as an example of the family. The broad, plump body of this insect is
obliteratively shaded, being grayish and pinkish white beneath, with some
faint markings, and shading into deep blackish brown above—on the upper
sides of the head, abdomen, and thorax. This brown upper side, moreover,
bears a beautiful, bark-like picture-pattern, made by narrow bands of light
olive-green upon the darker ground color. On the abdomen these bands are
simple and transverse, on the thorax and head they are beautifully branched
and netted. Though the Dogday Cicada has not strictly regular perching-
habits, it is an eminently arboreal insect, and spends most of its time clinging
to the bark of tree trunks and branches, in which situations both its counter
shading and its mottled pattern often come fully into play. When, as is also
frequently the case, it sits upon and among small twigs, either in trees or
bushes, it is apt to have more varied backgrounds, and its rich but none too
specially adapted obliterative pattern matches these nearly or quite as well as
it does the single plane of near-bark surface.

Some at least of the larger plant bugs—such as the stinking squash-
and fruit-bugs of eastern North America—are counter shaded. Anasa
tristis, for instance, the Common Squash-bug, is blackish above and yellow-
ish below. It lacks pronounced markings, although several of its kindred
have well-developed obliterative patterns, of various kinds. Probably, on
the other hand, some of them bear mimetic resemblances to parts of their
food plants. This is certainly the case among the Membracide, or Tree
Hoppers. These little insects are for the most part sluggish and still,
clinging close to the branches and twigs of trees, whose bark they perforate
with their sharp piercers for the sake of drinking the sap, which is their sole
nourishment in the adult state. When disturbed, they leap from their perch
with surprising force, and fly to another resting-place. Dr. Harris (‘‘ Insects

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Injurious to Vegetation,” p. 222) says of one species, which inhabits the
locust tree: ‘They never sit across the limbs, but always in the direction
of their length, with the head or fore part of the body toward the extremity
of the branches. On account of their peculiar form, which is that of a thick
cone with a very oblique direction, their dark color [without obliterative shad-
ing], and their fixed posture while perching, they would readily be mistaken
for the thorns of the tree . . .” Such mimicry of excrescences on twigs is
probably common to many members of the Tree Hopper family. Some,
however, have patterns which cannot well lend themselves to a simple mimetic
resemblance, and whose effect must tend rather toward obliteration. The
little Leaf Hoppers (Tettigoniida, etc.) are often very bright-colored—green
and red and yellow, in sharp, clear patterns—like tiny parrots. The effect
of this motley coloration, against flower-, leaf-, and stem-surfaces, is of course
obliterative—especially as the little hoppers are also counter shaded. Very
likely, however, there are also definite mimetic developments among them.
Plant lice or aphides (A phidide) are of various tints, from dark brown and
grayish black to fair, translucent green. Asa rule, their color closely matches
that of the plant surface on which they habitually feed and rest. Someof them
are blotched or speckled, but few or none, I believe, have truly elaborate
patterns. Nor do their costumes show more than a slight tendency toward
obliterative shading, although the actual translucence of some kinds nearly com-
pensates their lack of this device (—both weakening or even obliterating the
light-and-shade of their own bodies, and preventing their casting shadows
on the leaf- or flower-surfaces on which they sit). Some, in their early life,
are cloaked—and, likely enough, protected, though certainly they are not
concealed—by a covering, sometimes enormously developed, of white, soft,
cottony down. These white-tufted bark lice are a familiar sight on willow
and alder bushes.

Many other forms of hemipterous (and especially homopterous) insect
might be mentioned, but mainly to show their general dinginess of coloring,
which seems in keeping with their habits. Many of them are nocturnal and se-

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clusive, like the cockroaches and earwigs, and have little or no special costume-
development. Monochrome blackish, and unmarked, are also certain aquatic
forms which live exposed to the daylight, such as some of the Water Boatmen
(Notonecdide). It is likely that, for one reason or another, such insects are
little sought as prey by the higher animals. But many of the larger sub-
aquatic bugs are mud-colored, and some of them are decidedly pale-bellied.
Three important insect orders remain to be glanced at in this chapter,
namely, the Hymenoptera (bees, wasps, borers, etc.), Diptera (flies, mos-
quitoes, etc.), and Neuroptera (dragon-flies, ephemera, etc.). In these orders
obliterative shading does not play a uniformly dominant part. The insects
comprising them are for the most part winged, and not only winged but ac-
tively aérial, and depend much on their powers of flight for escape from enemies.
Some of them (dragon-flies, wasps, etc.) are themselves ferocious hunters,
and too big and active to be eaten by the smaller insectivorous birds; while
most of the flying Hymenoptera are terribly armed for offense and defense
with poison-injecting stings, so that they are avoided by the general run of
insectivores. Again, many of the Diptera and most of the Hymenoptera have
no fixed perching postures relative to the prevailing light, but sit both above
and under twigs and leaves, etc. This last fact alone is a sufficient reason
why these insects, as a class, cannot greatly profit by obliterative shading.
Some of them have it, to be sure; and it does work, more or less, when they
cling to the undersides of things, or sit on a surface perpendicular to the earth,
—provided, in both cases, that the surface belongs to an opaque substance,
and is of sufficient extent to cut off much light from the insect’s ‘underside.’
But since they also cling beneath slender twigs and translucent leaves, the
obliterative effect of their counter shading, when they have it, must often be
wholly upset, and this alone, as we have said, is reason enough why many of

these insects should be nearly or quite as dark below as above.*

*In this book the term counter shading, when unqualified, means shading from dark above
to light below. Insects like many Diptera that have their darkest details on their under side may profit
by this in situations we do not understand. In general, it is not safe to deny to any coloration what-
ever, concealing functions under circumstances not yet recognized —A. H. T.

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In spite of their toughness and their terrible weapons, the stinging Hy-
menoptera are preyed on by a good many birds; and though as a rule not
counter shaded, they are furnished with bold obliterative patterns of many
sorts. The predominant type, perhaps, is a system of sharp transverse bars
of dark and light, by which the insect is ‘cut up’ as the zebra is by his bands.
Yellow and black are the prevailing colors of these patterns—though white
and buff often take the place of yellow, and fuscous, tawny brown, and olive
(plant-shadow colors) the place of black. Such markings are fundamentally
and very potently obliterative against their wearers’ average backgrounds
of green vegetation in sunlight and shadow, and also amidst yellow flowers.
Sometimes the pattern is simplified to a ‘ruptive’ one of two or three broad,
unmarked patches of black and yellow, or black and orange—as on some
of the bumblebees,—or still further simplified to a nearly monochrome cos-
tume of mingled plant- and shadow-like greenish yellow. Some wasps and
bees, again, are uniformly almost black, and do not seem to have obliterative
devices of any kind—except in the cases where the black is transfused with
metallic color.* On the other hand, the transverse ‘secant’ pattern is often
highly elaborated, consisting of many narrow, sharply defined, contrasting
stripes, varied on the thorax and head by more broken and irregular mark-
ings. Such is the case with certain wood wasps or hornets, e. g., the common
“Yellow Jacket” (Vespa vulgaris). Among the “sawflies” and “borers”
(Siricida, etc.), there is much variety in coloration as well as form. Glossy
black, varied to steely blue, is perhaps the most characteristic color of these
insects’ bodies, but with it are often combined red, orange, yellow, brown,
etc., in comparatively simple ‘ruptive’ and ‘secant’ obliterative patterns.
Though lacking finer ‘bark-pictures,’ as well as counter shading, some of
these borers, etc., are very inconspicuous when seated on the trunks of trees.

The wings of most Hymenopiera—as those of most of the other aérial
insects mentioned in this chapter—are transparent, and hence essentially
inconspicuous at all times, except when they brightly ‘shine’—as a glass

* See footnote, p. 204.

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window may. Sometimes they are merely translucent, being clouded with
color,—such color, usually, as continues the background-picturing of the
head and thorax when the wings are folded. In some cases, again, the
wings are barred or spotted, and these markings have of course an oblitera-
tive tendency.

Iridescence is fairly common among Hymenoptera, and there are some—
chiefly small kinds—which are equipped with uniforms of intensely vivid
changeable color, ranging sometimes from bronze-red to blue-green or green-
blue—like the back of the jacamar* among birds, but still more brilliant.
Green is the dominant color of almost all such costumes, which are in the
highest degree obliterative amidst vegetation, as we have already seen.

Some flies, too, have obliterative uniforms of iridescent green and blue,
as everybody knows. They are, I believe, rarely or never as brilliant as the
very finest of those worn by Hymenopiera, though often very rich and beauti-
ful. The coloration of the Diptera in general differs but little, in essentials,
from that of the Hymenoptera. [The bolder patterns and colors of the
Hymenoptera fit their more energetic lives, which bring them against bolder
background differences.]} But as the dipterous insects are softer and more
defenseless, so are their concealing equipments somewhat more elaborately
developed. Many are counter shaded, and habitually perch on the tops of
things. Some of the more aérial, flower- and foliage-haunting kinds, have
bright, transversely ‘secant’ patterns of yellow and dark brown or black; but
this coloration is less characteristic of them than of the Hymenoptera. The
close likeness in color and pattern between certain stinging wasps or bees and
stingless flies has led naturalists to suppose that the flies are mimics of the
bees. This resemblance, however, is quite in keeping with the similarity in the
insects’ forms, habits, and environments, and less remarkable than many other
kindred cases which cannot possibly be connected with mimicry.

Flies are often dingily colored, and—especially those which have counter
shading and more or less finely mottled patterns—fitted for “lying close” on
* See p. go, Chapter XVI. { Interpolation by A. H. T.

206

dingily colored surfaces. But many kinds are too promiscuous in their perch-
ing habits to profit by highly specialized coloration. Some have transverse,
opaque, obliterative bands of dark brown on their fair, transparent wings,
which would otherwise often be made conspicuous by their unbroken glisten-
ing. So also these flies’ big, composite eyes are sometimes richly iridescent,
and therefore, amid appropriate surroundings, well ‘obliterated.’

The slender-bodied Diptera, such as gnats, mosquitoes, ‘long-legged dad-
dies,’ etc., show few or no very remarkable developments of protective color-
ation. Being perchers on tree trunks, branches, and the dead-leaf covered
ground, rather than on flowers and green leaves, they are usually dull colored—
brown or grayish. Few have noteworthy body-markings, but many are
obliteratively shaded. Their transparent (and often daintily iridescent) wings
are sometimes marked with obliterative spots or transverse bands of dusky—
as in some of the well-known and well-hated Anopheles mosquitoes, and some
of the ‘long-legged daddies’ or crane-flies (Tipulide)—while in others the wings"
are dusky brown with various opaque white markings. In fact, with a good
many dipterous insects obliterative wing markings largely take the place of
body markings, and the two broad wings when flatly folded amply mask the
body, from a top view.

Wingless Hymenoptera, or ants in their apterous phases, largely lack not-
able obliterative or mimetic (?) devices, apparently relying for defense on their
strong biting jaws and sharp acid excretions, as well as their extreme bodily
toughness,—and passing much of their time in dark retreats of their own
making. Their prevailing color is black or dusky brown, without obliterative
shading. But some are tawny yellowish, some rust-brown, and some wear two
or three of these earth-colors (including black), in clearly defined, unflecked
‘ruptive’ patches. Despite the sharply pungent acids they contain,—doubt-
less effective against some predators, ants are a favorite prey (sometimes even
the sole (?) diet) of certain birds and beasts, and it is somewhat curious that
they have not more highly developed disguises. Protective coloration would
not avail them, however, against the most greedily and exclusively formicivorine

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creatures, the ant-eating mammals, who dig open their strongholds and devour
them by the thousand at a meal.

The Neuroptera (for convenience I follow the old arrangement and include
the dragon-flies in this order) have, in the matters of outward form and dis-
guising-coloration, much in common with the aérial insects already considered,
but also a few salient points of difference. As everybody knows, the typical
dragon-flies (Libellulide) sit with their four large gauzy wings fully outspread
in a single plane. Too finely-netted to be perfectly transparent, these wings
(in addition to being iridescent) are very often marked with bold obliterative
bands or spots of opaque color, like that of sticks and bark and shadows—
brown, brown-red, dusky—and these markings go far toward making the
wings invisible against their average backgrounds.* The long and slender,
stick-like body also is often marked with obliterative cross-bars, and oblitera-
tively shaded. For the true dragon-flies, unlike most of the insects we have
been considering, habitually perch back-uppermost,—or sometimes vertically,
but rarely or never upside down. Hence in their disguisement there is op-
portunity for counter shading and picture-patterns to come fully into play.
The patterns they wear are of many kinds and many colors (green, red, yellow,
blue, and black perhaps predominating), but almost all are transverse and
most of them are very simple. Their counter shading of course takes in not
only the attenuate abdomen but the thorax and big head; in short, the whole
main form of the insect. The proportionately enormous compound eyes
are usually rather dim-colored, but more or less iridescent, and very inconspic-
uous. Gorgeous iridescent foliage-color—cold blue to golden green and
yellow—is common in the costumes of dragon-flies, and highly characteristic
of some groups. As they are bird-like in their light, upright perching and
sudden, swift, aérial sallies in pursuit of their flying prey (from which dashes

‘they often return to the same perch), so are they bird-like—though also like
butterflies and lizards—in the splendor of their obliterative, vegetation-picturing

* Their concealing-coloration probably serves them even more vitally in their aérial hunting
than as a protection.—A. H. T.

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costumes. The bodies (abdomens) of some kinds are so extremely slender and
long that they are almost unrecognizable as belonging to an animate creature,
looking more like grasses, sticks, leaf-stems, etc. Hence it would seem that
they might also be subjects for complete mimetic disguise. And in fact, a few
of the slenderest kinds have little or no obliterative shading, and present a close
mimetic likeness to definite solid details of vegetation. Some of these ‘mimics’
are rich brown-red, like many of the sticks and twigs and weed-stems
amid which they perch—others ochre-yellow like dead meadow-grasses,—etc.
The wings, however, rarely or never contribute to the mimetic effect, but
are almost always obliteratively marked, with various blotches and bands of
average background color. Among the Agrionide—less typical dragon-
flies which sit with wings folded, vertically and longitudinally—there are
probably cases of mimetic resemblance in which the wings play a part. On
the other hand, these exquisitely gracile and sometimes gay-hued A grionide
are often equipped for obliteration—body, wings and all. Some which live
always near water, usually perching close to its surface, have fair, bright-blue,
obliteratively shaded bodies, which match their average watery backgrounds,
under blue sky. Others have black, shadow-like wings, sometimes marked
with a few obliterative white spots. On the whole, however, obliterative
patterns, especially of the wings, are less in evidence among the Agrionide
than among the Libellulide or true dragon-flies.

Obliterative wing-patterns (both dark marks on light, transparent wings
and light marks on dusky ones) occur also among some of the groups of plainer-
colored Neuro ptera, such as the caddises, mantispians, scorpion-flies, ephemera,
etc.; though many of these insects, especially the smaller species, lack such
markings. Some, on the other hand, are colored throughout much like some
of the red or golden brown, obliteratively equipped true dragon-flies. In
general, the coloration of the smaller and dingier Neuroptera differs but little
from that of the corresponding dipterous insects. Few have highly specialized
disguises of either color or form, in the perfect state, though most of them
are obliteratively shaded. Nor, with a few exceptions, are the larve or pupe

209

of these insects, or of any of the insect orders mentioned in this chapter, of
much interest in the present connection. Such of them as are aquatic but
not mud-haunting are apt to have obliterative shading, more or less complete,
but their coloration is seldom or never highly specialized. The larve of dragon-
flies are mud- and dingy-bottom-colored, counter, shaded very scantily or
not at all, and they are wont to lie concealed under mud or bottom-rubbish,
leaving only their voracious heads exposed, ready for prey. Some hymenop-
etc.) feed on leaves in the daylight, like
lepidopterous caterpillars, which they resemble in many points of external
appearance. But they have, as a rule, some active defensive (?) equipment

terous larvee (those of “‘sawflies,”

(e. g., the power of jetting out pungent liquid), and their disguising coloration,
in most cases, appears far less specialized than that of many caterpillars.
(Some of these hymenopterous larve, indeed, in the rolled-up attitude charac-
teristic of them when at rest, bear a remarkable likeness to snail-shells. But
this is very likely a mere coincidence.) For the most part, the larve of the
Coleoptera, Hymenoptera, and Diptera live hidden away from daylight and the
attacks of the higher animals, except such as can dig or drill for them. Hence
they are colorless, or monochrome, without patterns. In the case of insects
whose metamorphosis is incomplete, like most of the Orthoptera, the earlier
stages much resemble the later in their disguising coloration.

Spiders

Spiders (Arachnida) assuredly rival insects in the variety and high devel-
opment of their disguising costumes. But we have studied them even less
than we have studied insects, and hence must pass them over even more briefly.

There are wonderful developments of out-and-out mimicry among spiders.
Many such cases have been described by naturalists, and many, doubtless,
remain to be discovered.

But ‘obliteration,’ not mimicry, is our theme, and obliteration is the rule,
not the exception, in the disguisement of spiders. ‘The many kinds which in

210

their perching have the requisite constancy of position relative to the prevail-
ing light, are, in almost every case, obliteratively shaded. Thus their great,
globular bodies are ‘flattened out,’ and, with the further aid of background-
picturing patterns, of one sort or another, practically effaced. Some wear
tree-bark and rock-surface pictures, more or less generalized, others leafy
or grassy ground pictures. Those which swing free in flat, open webs have
sometimes very bold and brilliant patterns—flower-like, dewdrop-like, and
like black shadow-vistas amid small, sunlit vegetable forms. Some of these
brightly patterned spiders have the upside-down habit, and their counter
shading is of course inverted, like that of so many caterpillars. Some of
them, with globose and highly colored abdomens, have slender, flat gray
heads, duly counter shaded, which in time of watch and quiet are laid against
a specially constructed patch or trail of glaucous, opaque web, which they
match exactly. (See Fig. 127.) The big, round abdomen, meanwhile, is
either separately but equally well ‘flattened’ by counter shading, and ‘merged’
by picture-patterns into its background of sunlight and shadow, grasses and
flowers, or it presents a mimetic likeness to some single, solid landscape-detail
—flower, berry, seed pod, or curled-up leaf.

‘Hole-picturing’ (Chapter XXII, Fig. 120) is a common detail of disguise
among the more richly patterned kinds.

The dainty white spider* shown in Plate XVI, Figs. V, W, X and Y, well
illustrates a fact to which we alluded early in the book, namely, the greenness of
foliage-filtered sunlight, potent in its visual effect on animals’ colors, particu-
larly white. In some views amidst sunlit leaves, this actually porcelain-white
spider (Figs. V and Y) looked even greener than Figs. W and X show him.

The next and final chapter will treat scantily of the most beautiful and
elaborately colored of all insects, if not of all animals, namely, the Lepidop-
tera in the perfect state, or butterflies and moths.

* This species has also a yellow phase.

CHAPTER XXVII

BUTTERFLIES AND MOTHS

I. Butterflies

HESE gloriously resurrected ‘‘worms,” these favorites of man from
ancient times,—creatures which he has been wont to consider purely

and simply bright and beautiful,—are in reality all tricked out in fine and
powerful disguising-costumes, which make them, each in its own special
situation and headquarters, invisible or scantily visible to their enemies.
Famed though butterflies are for their gay and wondrous gaudiness, there is
probably no single kind among them all whose coloration is not concealing,
in its true and particular environment, under the typical and appropriate
conditions. In civilized lands, species may and doubtless often do survive
their fittest environments, when these are destroyed by man. Hence it is
only in the primeval wilds—e. g., the great tropical forests—that the butter-
flies and their proper surroundings can infallibly be found together, and their
interrelationships rightly studied. Nor is it easy to imagine any pursuit in
natural history more profoundly fascinating than the study of the special
disguising-costumes of tropical butterflies. Even as the subject was known
to naturalists who recognized only mimicry and an exceedingly limited range
“cryptic” color schemes, it was already a large
and very interesting theme. But it has now grown beyond measure greater

of more nearly obliterative

and more interesting, since by the disclosure of the simple laws of true oblit-
erative coloration, it has been extended to include practically all butterflies
and moths.
If a man well fitted for the task were to devote his whole life to the study
212

of the disguising coloration of the butterflies (and moths) inhabiting say a
few square miles of Brazilian forest, he would doubtless be discovering new
wonders even of essential principle on the last day of his hunting.

Our own knowledge of the subject is of the slenderest and most frag-
mentary sort; nevertheless we can open several vistas into quite untrodden
fields of exquisite truth. Some few of our readers are already familiar with
my father’s paper on “Protective Coloration in its Relation to Mimicry,
Common Warning Colors, and Sexual Selection,” * wherein most of his
discoveries concerning butterfly coloration are clearly outlined. The present
chapter contains but little which was not at least foreshadowed in the above-
named paper, or in an article by me published in the Century Magazine
for June, 1908, and the reader must take it as a recapitulation and enlarge-
ment of these earlier essays.

In the first place, the obliteration of butterflies is a very different problem
from that of vertebrates, or even large-bodied insects. Obliterative shading
is but scantily called into play, for their principal members, their wings, are
flat and paper-thin. Their slim, cylindrical bodies are almost always counter-
shaded, to perfection, but this is, comparatively, a small detail of their dis-
guisement. Their great flat wings, with their characteristic outlines, have
to be disguised by other means. In the case of birds and beasts, etc., Nature
has to use artifice and deception to make them into ‘canvases’ for back-
ground pictures; but butterflies’ wings are actually flat planes, all ready for
the pictures. ‘These Nature gives them, to the highest imaginable degree,
ranging through a scale of variations marvelous in its immensity, yet fur-
nishing each species with a costume well fitted to its own peculiar mode of
life (although, as already explained, the perfection of the fitness may be
no longer discernible, since it is often marred by rapid, man-wrought changes
in a butterfly’s natural environment).

This great agglomeration of differing butterfly types (as far as it is known

* Published in the ‘Transactions of the Entomological Society of London” for December
24, 1903.

213

to us) may be separated, for our purposes, into several main groups,—such
as that of sedentary and that of aérial species. The division is somewhat
arbitrary, since practically all butterflies are strong of wing, and there is such
a multitude of intermediates connecting the two types that it is impossible to
draw a sharp line between them; nevertheless, the terms cover, in the aggre-
gate, an essential difference of characteristics. Among the sedentary species,
then, occur all the most highly wrought, minutely detailed ‘“‘cryptic” pat-
terns (a good many of which have been recognized as such by naturalists in
general). They are worn by butterflies which pass most or at least very
much of their time at rest, sitting motionless, with wings—in most cases—
folded perpendicularly over their backs. Some of them are developed mimet-
ically, even to an extraordinary degree—e. g., the famous leaf-mimicking
Kallima inachis, of India. There are many other pronounced though less
extreme cases of whole-leaf mimicry among butterflies, not only in the genus
Kallima, but in nearly allied as well as in some remote genera—and even
among restless ‘aérial’ species. One such, which I believe has never been
recorded, is that of the abundant and familiar South American Heliconius
melpomene. On wing amidst the uniformly bright-green lower foliage of the
tropical woods, it is as often conspicuous as any patterned butterfly could
well be. [The gaudy costume of this red-and-black Heliconius is evidently one
more example of coloration adapted to the wearer’s moments of greatest danger.
Haunting, while on wing, the thickest foliage, where birds cannot easily catch
it, it is probably most in danger when intently feeding among flowers. (At
such times butterflies sometimes allow themselves actually to be plucked off
their perch by one’s thumb and finger.) Probably this Heliconius finds such
an intoxicating feast in the tops of certain great flowering trees that it there
becomes an easy prey to any birds that want it.]* But in its nightly roosting
(begun in the early twilight), it is a leaf-mimic, of no mean achievement.
It roosts—as we have seen it—gregariously, several individuals (three to ten
or more) occupying the same leafless twig, beneath which, at pretty regular
* Interpolation by A. H. Thayer.
214

intervals, they suspend themselves, with closely folded wings. The under-
sides of these wings, now alone exposed, resemble the upper sides in pat-
- tern, but are very much dimmer, the black being replaced by ochrous dusky
brown and the red by soft, hoary pink. In addition, the lower wings are
narrowly bordered on the anterior edge with pale yellow, and the slender
body bears spots of the same color, while the bases of the fore-wings and the
immediately adjacent portions of the body are marked with small red spots.
Half of the broad pink (= red) wing-band shows beyond the tips of the folded
lower wings. The whole form of the insect thus folded and placed, though
without any very peculiar modifications of contour, is almost exactly like that
of many slender, entire leaves common in the forests it inhabits. But ob-
serve, it is not like a living leaf in color, nor does it (in our experience) im-
merse itself in a sea of foliage, there to be the single counterfeit among many
genuine originals. Instead, as I have said, it selects, with several compan-
ions, a leafless twig, in a spot where leaves are few, and together they suspend
themselves beneath this twig in the semblance of a row of drooping dead
leaves which still show traces of live color (the fine yellow lines and spots),
and are each marked with a partly faded pink disease-spot (the pink band
crossing the fore-wings) and some brighter red disease-flecks near the leaf’s
(= the butterfly’s) base. That this resemblance is not fancied, but real and
very potent, will, I think, be attested by anyone who studies the roosting-
habits of Heliconius melpomene. ‘There are doubtless many fine cases of this
sort of mimicry still to be discovered. But, as we have repeatedly affirmed,
mimicry is not our theme in the present book, wherein we must confine our-
selves almost wholly to the far larger and more intricate problem of obliter-
ative coloration. Nor is it to be supposed that mimicry rather than obliteration
is the rule in any large group of butterflies. On the contrary, the cases of
out-and-out butterfly mimicry are relatively very few indeed, and scattered,
while ‘obliteration’ is universally and most variously achieved among them.

Many of the butterflies which rest amid live foliage and flowers have
daintily detailed and at the same time ‘generalized’ pictures of their varie-

ore

gated and varying backgrounds of more or less distant leaves, twigs, blossoms,
etc., with their lights and shadows, and with vistas through the nearer back-
ground to the further. Such patterns occur on both the upper and the under
sides of the butterflies, but are usually minutest on the undersides. They are
characteristic of species which sit with motionless folded wings—or in other
words, those of the ‘sedentary’ type. Some of the South American species
of the genus Metamorpha, as M. dido, are good examples. So, of a some-
what different type, is the European ‘‘Orange-tip” butterfly (Euchle car-
damines) whose floweret-picturing is well known. (See Fig. 128.) This
is in part almost mimicry, though compound, for the nearer flowers look as
near as the actual wing-surface on which they are rendered.

More restless kinds, which alight only momentarily, keeping their wings
outspread, or continually opening and folding them, have more generalized
leafy or flowery background-patterns, often strongest on the upper side.
These we will discuss more in detail later, when we have finished our frag-
mentary review of the group of ‘sedentaries’ or closed-winged perchers, the
butterflies whose most highly specialized obliterative coloration is on their
under -sides. This group may be subdivided as follows: 1. True leaf mimics
(already mentioned, e. g., Kallima inachis and Heliconius melpomene.) 2.
Those butterflies whose obliterative pattern pictures a varied background of
live leaves, flowerets, and other richly colored details of living (and dead)
vegetation (already mentioned, e. g., Metamorpha dido, and, in part, Euch-
le cardamines). 3. Obliteratively colored bark- (and rock-) butterflies.
These are many, although bark-picturing patterns in their supreme develop-
ment are more characteristic of moths than of butterflies. All (?) the multitu-
dinous moths which are addicted to perching on tree trunks sit with wings
flatly applied to the bark, whereas the butterflies of like proclivities, with a
few remarkable exceptions, of which I shall soon say more, keep their wings,
for the most part, perpendicularly folded, so that their background—that of
their full side view—is necessarily much more variable. Nevertheless, many
of these butterflies bear colors and minute patterns on their undersides which

216

Fie. 128. Four Orange-Tip Butterflies (Huchloe cardamines) on
cow-parsley, showing the flower-picturing on their undersides, and
the ‘cutting down”’ of their out spread topview to a flower-like form
by darkish tips. 8

Photographed from nature by Percy Collins.

on the borders of the forewings.
Photographed from nature (dead but‘erfly).

Fic. 129, Butterflies on vegetation (Papilio ajax, P. asterias
Basilarchia artemis, and Argynnis idalia), their dark patterns
merging with the shadowed portions of their backgrounds, leaving
their light markings standing out like lighted leaf-and-flower forms,
at various distances.

Photographed from nature. (Dead butterflies).

Fie, 131. Small Tortoise Shell Butterfly (Va-
nessa urticw) outspread on stony ground. His
light border-patterns carry the aspect of the-
background into his wings, disguising their real
contours, and making him look like a hole over-
Fig. 130. Light-colored (pierine) butterfly with background shadow-pictures

lapped by lighted ground-details.
Photographed from life by Cherry and Richard Kearton.
Courtesy Cassell and Co.

are decidedly of the tree-bark (or rock-surface) type. These patterns are
at once finer and less fine than those of the flatly-applied lepidoptera. Less
fine, as they less minutely and exactly depict one especial type of surface in
one especial view; more fine, in that they combine the elements of several
varieties of background at somewhat varying distances,—the bark of the tree
on which they sit, with its markings lessened by distance and foreshortened
in extreme side view, front or side views of bark-surfaces on other, farther
trunks or branches; or even still more extended vistas of the mixed forest
background. Examples of this type, in full and simple development, are the
several familiar northern butterflies of the genera Grapta and Vanessa, as
well as many nearly or remotely allied tropical forms. Tree trunks, tree
branches, and rocks are the characteristic resting-perches of these butter-
flies, though they are by no means confined to them—any more than their
patterns, beautiful and efficient for ‘obliteration’ though they are, show
that ultimate touch of specialization which would best qualify their wearers
for strictly specialized perching-habits. They are swift, sharp fliers, these
Graptas and others, and their upper sides have as a rule wholly different col-
ors and patterns from their lower, with different obliterative functions. But
that is another story, to be told later in the chapter.

Some of the much larger tree-trunk butterflies which habitually sit with
folded wings, such as the famous Calligo eurylochus, and others of that genus,
miscalled ‘‘Owl Butterflies,” have a subtile obliterative pattern in which the
picturing of near tree-bark is almost wholly replaced by that of more ex-.
tended and diversified vistas of the brown forest interior—a pattern, in short,
more like that worn by certain forest birds, such as the Ruffed Grouse. (See
Plate II, and Chapter VI, pp. 38-41.) This accords with the fact that, owing
to their great size, these butterflies can almost never have as a complete back-
ground for their ‘profile’ the bark of the tree on which they are perching,
as the small Graptas, etc., often can. (This is all the more likely on trees
with rough and flaky bark—a condition more characteristic of northern trees
than of those of the Calligo’s native forests.) The species of Calligo which

217

we have studied at large, perched, as we saw it, rather near the ground, often
within a. few inches of it—and there are evident traces of ground-‘picturing’
in its beautiful mottled pattern. Thus it is something of a connecting link
between the tree-bark butterflies and our fourth group of ‘closed-winged
sedentaries,’ the ground-picturers. The variety in the at once epitomized
and generalized ground-picturing patterns worn by these low-perching but-
terflies is almost boundless, and it would be folly for us here to attempt any-
thing beyond a brief general description of a few main types. Some of the
species belonging to this group are haunters of open fields and meadows,
and there is accordingly a frequent outcropping of grass- or even field-flower-
picturing in their costumes. But by far the greater number, at least among
tropical butterflies, are sylvan, and the most prevalent feature of their widely
varying patterns is the picturing of prostrate dead leaves and sticks. In one
form or another, in more or less clear development, almost all the sylvan
ground-perching butterflies wear these pictures. Such things as several dead
leaves together, overlapping, each with a dark shadow underneath its border,
blent softly on one side and on the other ending in sharp contrast against the
bright edge of the leaf which casts it; leaves partly curled up, with holes and
ragged borders, crowded and distorted in perspective; dull sticks with clear-
cut shadows, bright, strawlike sticks standing out over broad, blurred shad-
ows; or objects like these combined into fine, sharply mottled patterns by per-
spective,—such are a few of the commoner details of the unlimitedly various
backgrounds of forest floor against which these butterflies are seen, when
they are seen at all; and such, by the same token, and in very truth, are the
details of their equally various and marvelously potent obliterative picture-
patterns. Being such little creatures, and sitting so low down, they are secure
of comparatively near backgrounds—telatively, for instance, to the species
which perch high up on small twigs and leaves, or even those that sit with
perpendicularly folded wings on tree trunks. On the other hand, their case
is different from that of the flatly applied lepidoptera, whether moths or but-
terflies, and whether of tree trunks or the ground, in that their backgrounds
218

are almost always at least a few inches distant from them, and subject both
to much variety and complexity of detail and to a good deal of refinement and
distortion by perspective. Some of them, indeed, wear rich, varied ground-
scenery pictures, scarcely rivaled by those of the most finely patterned forest
birds. Others are colored very simply, with either many very faint and
delicate or few and bold obliterative markings.

Passing now to the class of aérial butterflies, i. e., those which spend a
much greater proportion of their time in flight, and do not characteristically
“sit close”? on perches, we find, of course, new general schemes of coloration.
But as I said before, the two classes are by no means clearly separate, and
hence their distinctive color schemes are subject to interminglement, of many
forms. In the first place, most of the ‘sedentary’ wing-folding butterflies,
such as we have been considering, are ‘aérially colored,’ so to speak, on the
upper side. That is, their upper sides bear either such colors and patterns
as decrease to the utmost possible degree their inevitable conspicuousness in
flight, such as tend to obliterate the wings of the perching insect when they
chance to be expanded, or such as ‘dazzle’ in the way mentioned in Chapter
XXVI, p. 199, and of which the reader is soon to hear more. (‘Dazzling’-
colors of this kind, indeed, are confined, in their full development, to close-
folding ‘sedentary’ butterflies, and, contrariwise, there are few such butter-
flies whose upper-side colors do not on occasions perform this ‘dazzling’-
function, however largely obliterative may be their general use.)

There are butterflies which alight very often, but do not stay long in one
place, and either keep their wings outspread, or are continually closing and
opening them. These, intermediate between the sedentary and the aérial
types, share the color schemes of both,—perhaps inclining, in costumes as in
actions, to the aérial. Their trick of wing-waving, however, is common, in
more or less pronounced form, to most butterflies,—some of the tight-folding
‘sedentaries’ alone being nearly exempt from it. (In conjunction with the
less minutely detailed patterns of many of the species that practice this trick,
it would seem to be a general measure for ‘assimilation’ with their surround-

219

ings—a movement imitative of the swaying and trembling of the nearly always
breeze-blown leaves and flowers and twigs amid which they sit.) Even when
perching, these butterflies of the ‘intermediate’ class expose the upper side
as freely and fully as the lower, if not more so, and in many cases the upper
side is the more specially and minutely patterned of the two. The prevailing
color of all such butterflies, or at least the color which occurs almost unvaried
on the greatest number of species, is dusky olive brown,—‘black’ which is
not black. This is just the average tint of the smaller shadows amidst vege-
tation. On this groundwork of perfect shadow-color are painted all sorts
of leaf, sun-fleck, and flower-pictures—more delicate and elaborate on species
which more frequently alight, bolder and simpler on the more constantly
aérial kinds. (See Fig. 129.) The commonest tint of the light ‘picture’-
markings, which stand framed in the pure, elusive shadow-color, is bright-
(often somewhat greenish) yellow,—and this, after white, is the color of the
majority of flowers. Furthermore, it is the color—barely clarified—of almost
all brightly sunlit foliage. No wonder, then, that the presence of this color
in clear and delicate generalized picture-patterns, with the due amount of
contrasting, dusky shadow-tint, strongly tends to ‘obliterate’ the broad, flat
wings of butterflies. So many and so various are these picture-patterns, in
kind and in degree (of elaboration and finish), that it would be hopeless for
us here to attempt a comprehensive account even of the main types of them.
Here as elsewhere in our book, the description of a few characteristic cases
must suffice.

Papilio polydamas, of North America, and some of the dark Satyrine, will
serve to typify the butterflies which have a shadow-like ground-color overlaced
with bright, generalized pictures of living vegetation. Some of these, Papil-
ionide especially, have such patterns beautifully clear on the under as well
as the upper sides, and often rest with tightly folded wings. The patterns of
their under sides, in fact, though usually less bold and bright than those of the
upper, are also as a rule more fine and delicate, as if to admit of a closer in-
spection. And in truth it is chiefly at times when the butterfly has relaxed

220

its vigilance and is sitting more or less inert, that the pattern of its under-
side is displayed in full. Also, the side view is apt to have a somewhat more
distant background than the full top view,* and hence requires a more deli-
cate pattern for ‘obliteration.’

Sun-flecks are another important feature in these picture-patterns of the
Nymphalide, etc. They are big circular marks of yellow or whitish, some-
times rimmed with violet or blue, and set in leaf-shadow color. The blue
border is a mere intensified rendering of the sky-tinged rim around real sun-
flecks, which are in fact camera-obscura images of the sun surrounded by
blue sky. Such markings are worn for instance by Nymphalis bolina and by
the male of Hypolymnas misippus. Usually, as in the case of H. misippus,
the encompassing dark tone (with or without a skyey rim) ends in sharp
contrast against the spot; sometimes, however, it is blended into it, as is the
case with real sun-flecks also. Then there are sun-streak pictures—mark-
ings that depict sharp ribbons of sunlight alternating with bands of dusky
shadow. Patterns of this kind are a most characteristic element of some
woodland scenes, particularly in tropical woods, amid fringed palm leaves,
and other, smaller, finely pinnate foliage,—and bright pictures of them are
worn by some of the butterflies inhabiting these forests. Heliconius chari-
tonia, of the West Indies, etc., is a fine example. Indeed, the disguising-
coloration of this or a closely allied butterfly has been, ere now, in part, well
and accurately analyzed and described—by Mr. C. W. Beebe, of the New
York Zodlogical Park. But such a costume as Heliconius charitonia wears
is not limited to the single function of still-sun-stripe-and-shadow picturing
described by Mr. Beebe, admirably though it serves that function. It is also
highly ‘obliterative’ as the Heliconius flies about rather slowly amid feath-
ery, sunlit foliage. The irregular and not rapid motion of the butterfly’s vividly
striped wings fits into and merges with the mazy scintillations of the fine-cut,

* Because the butterfly is likely to be in closer contiguity with the nearer details of its back-
ground when flatly outspread, than when folded and projecting outward perpendicularly from its
perch.

221

waving leaves, sunlit and bright above dark shadowy interstices. Again,
when the Heliconius is quietly perching, its yellow marks may produce the
effect, additional to that described by Beebe, of vistas through shadows or
dark twigs to a more distant sunny background. In fact, this effect is inter-
changeable with the other (that of light details or marks laid on or standing
above a shadowy background) in almost all the numberless obliterative pat-
terns of this general character, both on butterflies and on other animals.
According to the creature’s position and the character of its background, at
any given moment, its pattern will incline toward one or the other of these
two equally deceptive and obliterative effects.

The beautiful South American Metamorpha dido, already mentioned
among ‘close-folding sedentaries’ wears on its upper side a bolder green-
and black-laced pattern, which makes it extremely ‘dim’ and elusive in its
flight amidst foliage. But this pattern must also on occasions serve the but-
terfly at rest, for though cruder than that of the underside, it is too delicate
in detail to be merely a flight-pattern. For flight of course tends to cancel
the visibility of markings, blurring and blending forms and colors, and even
on the most slow-moving butterflies only big, bold patterns can maintain
a clear effect in flight. Many of the more aérial butterflies have such big,
bold patterns, however. In addition to the types described and figured
above, those represented by some of the other Heliconide, and some of the
South American green and black and red Pafilionida, are notable. A but-
terfly thus patterned with black and yellow (e. g., Heliconius sara), or with
black and green and red (e. g., Papilio gargasus), will never at any point in
its airy course relieve clearly, in full contour. As it passes across shadowy
interstices amidst vegetation, its black will disappear, leaving in sight only a
skeleton pattern of yellow, or green and red; and while it is passing brightly
lighted leaves and flowers only the black will show. Thus the watching eye
is condemned to see only flickering glints of color, instead of seeing the whole
form of the moving insect, as it would were the insect monochrome. Such
constantly repeated metamorphoses of aspect, amid the vegetation’s varying

222

movements, must strongly tend to baffle a pursuer. Heliconius melpomene has,
as I have already mentioned, a still simpler ‘ruptive’ flight-pattern (on its upper
side), and one which seems but poorly fitted to disguise it among green leaves
alone. Some of the beautiful Hummingbird Papilios of South America have
much the same coloration, with the addition of a pair of sea-green or pale-blue
spots. Such are Papilio gargasus and several kindred species. This colora-
tion is admirably fitted to disguise its wearers when they hover, hummingbird-
like, over, or momentarily perch on, gay-colored and brightly lighted flowers
which relieve against shadowy underspaces. But Heliconius melpomene, as we
have seen it, is less of a blossom-haunter, and with its still simpler pattern, of
black and red alone, it is not always as inconspicuous, even in its transitory
flower-attendance, as patterns could make it,—as patterns in fact do make
many of its relatives.* Like the Scarlet Tanager, however, and other some-
what anomalously costumed woodland birds, melpomene is a haunter of dense,
protecting foliage. ‘Through the mazes of woodland greenery it threads its
rather leisurely way with wonderful adroitness, flying with short wing-beats
and much sailing, and its skill in dodging in and out and round about amid
leaves doubtless makes it a difficult quarry for flycatchers. -There are many
ether remarkable South American tropical butterflies of the same long-winged
type. Especially noteworthy are those of one of the so-called “Batesian and
Miillerian mimicry groups’’—such species for instance as Lycorea atergatis,
Tithorea megara, Mechanitis veritabilis, etc. Their general scheme of colora-
tion shows much affinity with that of Heliconius charitonia, and much also with
that of certain types of the terrestrial tight-folding class. So also in their habits
they are nearly midway between the two extremes. They perch low down in
the forest, often very near or even on the ground, and their costumes contain a
good deal of rich ground-brown—the universal brown of the tropical under-
world, described in Chapter XIX. But though not, like Heliconius charitonia,
sara, melpomene, etc., truly ‘aérial,’ they are restless, and spend much time on
wing, often rising into the borders of that region of abundant foliage and fre-
* See the interpolation on p. 214.

ree

quent sunbeams which is the headquarters of sara, and other yellow and black
or green and black ‘aérial’ butterflies. In their perching, too, they show
infixitude of habits, often sitting with wings closely folded and sometimes
with wings more or less expanded. Their upper and lower sides are much
alike, but the lower has usually a somewhat finer pattern, which is highly
‘obliterative,’ although less definitely and minutely ‘ground-picturing’ than
most of the patterns worn by true terrestrial ‘sedentaries.’ In fact, the
costumes of these more sluggish ‘‘heliconoid’”’ butterflies contain just such
a compromise between bolder obliterative flight-patterns, in foliage and sun
and shadow tints, and finer, brown-ground-picturing perch-patterns, as a
knowledge of their habits would lead us to expect. The supposed mimetic
interresemblance of these butterflies’ costumes was alluded to, though not
specifically, in our Introduction. Another group of South American butter-
flies. believed to show the same sort of mimicry is made up of species with
more or less transparent wings. These also are aérial, their wings are long,
and marked, in various patterns, with opaque bands and spots of dusky, or
sometimes brighter color, inclosing spaces of pure glassy transparency. Of
course these insects are normally almost invisible, not only when they sit still
(with a background of green leaves or brown ground, or what-not) but even
in their leisurely flight through the forest aisles. ‘One of these clear-wings,”
says Bates, the great English naturalist, in his wonderful book “A Naturalist
on the Amazons,” “‘is especially beautiful, namely the Hetera esmeralda; it -
has one spot only of opaque coloring on its wings, which is of a violet and
rose hue; this is the only part visible when the insect is flying low over dead
leaves, in the gloomy shades where alone it is found, and it then looks like
a wandering petal of a flower.”

Iridescence plays a great part in the ‘obliteration’ of butterflies, especially
aérial ones. Indeed, splendid iridescent colors are enrolled in the service
of the more restless butterflies with an amplitude and variety scarcely to be
matched in the world of birds. We have already (Chapter XVI) given a
general analysis of the obliterative power of highly changeable color. The

224

reader will readily perceive how well adapted butterflies are to profit by this
factor of disguise. Though prevalent in almost all the main butterfly groups
already named, and often playing a part in minute picture-patterns, lustrous
changeable color reaches its highest development among aérial species, and
especially those of the skyey over-realm of tropical woods (Chapter XIX, pp.
107-108). Its range of tint is chiefly from reddish purple to golden green—a
scale which includes all the hues of open sky and sunlit foliage, and glowing
interstitial shadow. Sometimes, for instance, as in the case of some of the
big South American Morphos, almost the entire upper surface is covered with
immaculate iridescent color. These glittering blue butterflies are for the
most part highly aérial, and their color works like that of the peacock’s neck
(see Plate I), matching, in flashes, sky and sky-lit foliage, etc. Some of them,
on the other hand, are also much given to perching low down in the forest,
and here their vivid blue, in codperation with their brown, picture-patterned
undersides, achieves ‘dazzling coloration,’ of the active, metamorphic sort.
The bright color of such species is apt to be less iridescent and shiny than
fixedly lustrous, shifting somewhat in minor tints and in intensity, but in
main effect staying always blue, whereas the blue of the more aérial and tree-
top-haunting Morpho anaxibia, for instance, shifts to purple and to green in
vivid play and interplay of keen metallic tints. The ‘dazzling’ effect pro-
duced by some of these Morphos’ costumes is often most pronounced. Imag-
ine watching such a butterfly as it sails along through the brown aisles of a
South American jungle. Its broad, immaculate blue wings look almost lu-
minous in their glaring brightness, and the eye follows them easily and fasci-
natedly along their course. Suddenly the butterfly alights, folding its wings
sharply together, and—is no more. The eye must be well trained indeed to
recover from its ‘dazzlement’ in time to mark the insect down exactly. It is
like trying to see clearly after staring at the sun. More than this, the abrupt-
ness of the metamorphosis, the instantaneous eclipse of the bright thing which
the eye has been following, has in itself a very confusing effect. The butter-
fly sits motionless, and will not stir its folded, dark-brown wings, covered with
225

forest-pictures, until its disturber comes within a few feet or even inches of it,
when it expands them suddenly and goes flashing off through the forest, only
to repeat the trick. This kind of ‘dazzling’ is doubtless a frequent factor,
of greater or less relative importance, in the disguising coloration of butter-
flies, and also of moths, which we shall presently consider in some detail.

Lesser iridescence—the soft, masking sheen of bright, or especially of
dusky, markings, is common to a vast majority of butterflies—as, indeed, of
highly patterned animals of all classes. Its obliterative effect is constant and
essential. Such lustre of dusky markings in a butterfly’s picture-pattern is
frequently offset by a complete sheenlessness of the accompanying light-col-
ored stripes or spots, and this combination is potent to ‘obliterate.’ For the
dark parts, with their ever-varying play of soft rainbow-sequences of tint,
together form, as it were, a sort of fluid medium, a positionless, mutable at-
mosphere, in which are suspended the definite and sharp details of the pic-
ture-patterns, with their fixed positions. Or, to express it still more figura-
tively, the butterfly has first been converted into space, and then that space
furnished with such material details as it should normally contain. Not
merely among butterflies, but throughout the animal kingdom, such minor
lustrousness is a common and important factor of obliterative pattern. A
perception of its use is indispensable to a full understanding of obliterative
coloration.

So far we have considered butterflies’ patterns chiefly with regard to their
ultimate effects of ‘background-picturing.’ We must now examine more
particularly the principles which underlie these effects, the principles of the
intrinsic ‘obliterativeness’ of patterns. These have been touched on in our
earlier chapters, but since many of them show up in much clearer application
in the costumes of butterflies than in those of any other animals, they shall
here be described anew. The term ‘dazzling coloration,’ in its widest
sense, might include them almost all, for they almost all deal with devices
and systems of devices for the reduction of one form’s or detail’s conspicu-
ousness by the blazoning of some other detail. The butterfly’s organic form

226

possesses characteristic actual contours and internal details; these, if the
butterfly is to elude the eyes of its enemies, must be made as inconspicuous
as possible. How should this be done—how has Nature done it? By the
introduction of sham details, of such plainness, and so bestowed on the but-
terfly’s surface, as to eclipse and neutralize the real but faintlier showing
details and contours. The stronger the pattern appears, the dimmer appear
the forms and outlines of its wearer—as the reader has been shown. Patterns,
then, in the obliterative costumes of butterflies, are so placed as fundamentally
to thwart the conspicuousness of their wearers’ forms; and, at the same time,
the resultant effect of these intrinsically ‘dazzling’ and ‘obliterative’ mark-
ings, under the normal conditions, is of perfect pictwre-pattern. These two
principles, in fact—if indeed they can be called two—work in practically
inseparable combination and codperation. Thus is achieved for butterflies
the highest possible degree of average inconspicuousness—as, indeed, it is
achieved for the many other types of animal we have considered. Only, the
case of butterflies is simpler, because the third great principle, obliterative
shading, being confined to their bodies, plays, as to area, a comparatively small
part in their disguisement.

Let us look at a few concrete examples of these more subtile phases of
‘dazzling’-coloration. ‘There can be no doubt that the entire arrangement
of markings on the most brilliantly and elaborately patterned of butterflies
is hostile to the conspicuousness of the insect’s general form: let us then con-
sider some of the details of this ‘eclipsing’-system. Among the markings
whose function is the masking and ‘breaking’ of external contours, two are
especially notable. One is the diagonal cross-band at or very near the end
of each fore-wing, which ‘cuts off’ a bigger or smaller tip, thus marring
the characteristic outline; the other is a band, or more commonly a series of
spots, following more or less closely the real contour, in just the right position
to neutralize the real contour’s conspicuousness by distracting the eye’s atten-
tion to the anéi-contour’s vivider details, which serve as background-pictures,
and are as a rule supported in this effect by other and more varied internal

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patterns. Dark is conspicuous against light, and vice versa—accordingly,
light-colored butterflies are apt to have dark tips and borders, with such in-
ternal contours as work to bely the insect’s form when these markings ‘merge’
with dusky backgrounds, while dark-colored butterflies are apt to have cor-
responding light-colored markings. (See Figs. 130-131.) As we have seen
in earlier chapters, a living animal in nature is subject to momentary vicissi-
tudes of dark and light ‘relieving.’ When one side of a bird shows dark
against its background, the other side, seen from the opposite direction, is
very apt to be ‘relieving’ light. Hence, in very many cases, the best a crea-
ture can have in the way of generalized disguise is the clearest development
of ‘ruptive’ pattern, made of sharply contrasting light and dark marks. It
is this ‘ruptive’ effect that seems chiefly aimed at in the costumes of many
butterflies, though the resultant appearance is nearly always of adequate
‘picture’-pattern. Their background is to be a changing patchwork of
dark and light, and they themselves are to be both shadowed and lighted, in
rapid, ceaseless alternation; hence they must wear both dark and light in
sharply contrasted, form-belying patterns. ‘Tip-clipping’ bands of dusky
are very characteristic of light-colored butterflies, including some which bear
a mimetic likeness to single flowers. Of such mimics there are doubtless
many. But this flower-like-ness is seldom or never minutely perfect in the
sense of the leaf-like-ness of Kallima, though sometimes very effective. Cases
of this sort may be found among field butterflies, notably the Pierine. These
are usually yellow or white—the commonest colors of flowers—with scanty
markings. ‘Their fore-wings, however, in the cases in point, are ‘clipped
down’ to a shape more normal to flower petals by diagonal dark tips. That
is, these tips, being of the regulation ‘interstitial shadow color,’ strongly
tend to look detached from the light-colored wings, and merged with the shade
beyond. Often these dark rims or tips—as also others of the larger shadow-
picturing patches of dark color on butterflies—contain small markings; dim
ones, like faint pictures of more or less distant plant-details in shadow; bright
ones, like lighted near details above the shadow; pure white dots which
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look much like little gleaming dewdrops. Another characteristic marking of
these light-colored, flowerlike butterflies is a quartette of small dark flecks—one
fleck near the middle of each wing—which form, with the two club-tips of the
antennz, when the insect is symmetrically outspread, an almost perfect circle.
These six little marks look much like stamens, and greatly enhance the flower-
aspect, which often is yet further helped by a dusky clouding of the inner
portions of the wings, blending outward into light and inward darkening
toward the dark body; all of which produces a flowerlike appearance of
concavity.

But to return to the subtler ‘dazzling’ coloration of the background-
picturing butterflies. One more important special marking of this kind must
be considered, namely, the so well-known ‘ocellus’ or eye spot, a marking
which occurs in many forms and on many animals, but probably reaches its
highest development among birds and butterflies. At its full, as it appears
on the Argus and Peacock Pheasants, and on several butterflies, an ‘ocellus’
is a clear and strong representation of a sharply shaded sphere, or even of a
ball and socket, forms which may fairly be said to represent the quintessence
of substantiality. Among ocellus-bearing butterflies, the genus Calligo is
particularly notable. Some of the members of this genus, such as C. eury-
lochus, are popularly known under the misnomer of ‘‘Owl Butterflies,” from
the remarkable but undoubtedly fortuitous (?) resemblance of their under-
side, when the wings are outspread, to the face of an owl, with wide-open eyes.
The Calligos have already been mentioned among close-folding butterflies
whose undersides bear an exquisite picturing of more or less extended brown
forest views. In the midst of these finely marbled forest-pictures stand the
big, black-and-yellow eye spots, one on each hind wing. Except in flight—
when, indeed, the markings of the underside are so shadowed and jerked
about that they have little effect of any kind—only one ocellus can be seen
at a time, for the perching butterfly always (?) keeps its wings perpendicularly
folded. Each obliteratively-patterned side bears its one bold ocellus, which
acts as a loadstone or ‘dazzler’ to the sight, diverting it from the faintly-

229

traced outlines of the wings, and helping all the faintly-patterned part of their
broad surface to ‘melt away’ into the background. (See Fig. 132.) The
sharply visible ocellus, therefore, either seems to be standing alone in air, or,
more characteristically, ‘recedes’ with the rest of the wings’ surface, and passes
for a detail of the background. In either case, although in itself highly visible,
it looks like nothing edible to insectivores, while by its very brilliance it masks
and hides the organic forms of its wearer. Such is probably the main use of
major ocelli in the disguising costumes of butterflies. Manor ocelli are often
purely and simply details of background-picturing. Some, for instance, seem
closely imitative of gleaming dewdrops, and of dewdrops surrounded by shadow,
while others look like holes in leaves—dead or living, as the case may be. Some,
especially of moths, are actually transparent. Between minor and major ocelli
there is a smooth gradation, a complete chain of intermediates, and here as in
all such cases it is impossible to know just where one function ceases and the
next begins. Indeed, the two functions are more or less coérdinate and inter-
woven throughout this whole gradation, for the biggest, most specialized
‘dazzling’ ocellus achieves its full service only when it passes for a detail of the
background, and, on the other hand, the smallest accessory detail-picturing
one has a share of intrinsic obliterative or ‘dazzling’ effect.*

The multifarious obliterative devices of color and pattern worn by butter-
flies and moths are often seconded by modifications of external form, by
appendages, as in the case of birds and other animals. But the lepidopter’s
appendages are much more limited in kind, consisting almost exclusively of
modifications of the outer edges of the wings. These are cut-in, in gentle
curves or sharp, angular notches, or extended outward in longer or shorter,
broader or narrower ‘jags’ or “‘tails,”” of many forms; in short, they are altered
much and variously from the simple, average butterfly-shape. On the other
hand, may it not be that even the ‘normal’ butterfly wings, so grotesquely
large for the body, and so wonderfully marked for obliteration, are themselves

* This book aims to discuss only concealing-functions, though not forgetful of the obvious un-
limitedness of the uses that Nature must make of every detail.—A. H. T.

230

Fic, 182, “Ocellus’” or eye-spot on a butterfly model. ‘Dazzling’ effect, etc., see page 230, chapter XX VII. :
‘The ocellus distracts the eye’s attention from the contour of the cardboard butterfly on which it is painted, and which, by likeness of shade and
color, ‘merges’ with its background ; also, the ocellus itself, when the butterfly is not detected, seems, rily, to be a detail of the barkgronnd,

Fic. 133. Moths, butterfly and pheasant’s tail resolved by picture-pattern into representations of twigs and leaves

projecting over holes and shadows (Cf. Fig 120.) Polyphemus moths, BB, Pro ” Anti i
moth A, and Copper Pheasant’s tail E. 2 , BB, Promethea moth C, Antiopa butterfly D, Cynthia

obliterative ‘appendages’? For the wings of most lepidoptera, and of all
butterflies, are, judged in comparison with other aérial insects, and even the
most aérial of birds, out of all proportion to the size of their bodies. A butter-
fly with a wing expanse of about seven square inches weighs about a tenth
of an ounce, or less; a bee of about the same weight, with highly aérial habits,
has a wing expanse of only about a third of an inch; and a much-flying bird,
e.g., the Red-tailed Hawk (Buteo borealis), weighing about forty ounces, has
only about four hundred square inches of combined wing and tail expanse.
In other words, the butterfly has about twenty times the flying-spread of the
bee, and at least seven times that of the hawk, in proportion to its weight.
Indeed, a butterfly is so greatly ‘overwinged’ as to be incapable, in most cases,
of steady or swift flight. Its big vans float and flutter like wind-borne leaves,
carrying the little body which wields them in a tortuous, uncertain course, and
making it bob up and down with every stroke—a puny and unstable fulcrum.
To one who recognizes the power and importance of obliterative coloration,
it seems by no means unlikely that this monstrous expanse of wing among
butterflies (and some moths) is actually in itself an obliterative device—that
its chief use is the delusive and effacive extension of the little edible butterfly
outward into the environing vegetation and the background scenes. In
every case(?), the little body itself has the very acme of obliterative coloration,
based on complete counter shading. For the side view, when the wings
are perpendicularly folded, it is often daintily picture-patterned; in a top
view it is usually the center of dimness in a dim, smoky, blended patch of
pale half-shadow tint. Literally the center of dimness—the dimmest and
least noticeable part, from which the eye is led outward to the more or less
bright markings of the widely extended wings. But these bright markings
themselves are, as we have seen, potent parts of the disguise, since they picture
the landscape, and lead the beholder to think he sees through and beyond
where really there is an opaque surface interposed.

Here, then, is an amusing contrast between old ideas and new. On the
one hand, a butterfly is hailed as the very embodiment and epitome of gay,

231

bright, careless life,—a dancing elf, a creature beautiful for beauty’s sake
alone, a reveling fellowship of four animated, glittering, flowerlike wings;
while on the other hand, if we follow this new supposition, we see a butterfly
as a harassed mite of vitality, for harsh need’s sake encumbered with huge,
masking shields, richly enwrought with illusive pictures of the scenes amidst
which the mite of vitality dwells. The bee’s wing and the hawk’s wing are
evidently formed for action, and for action only, whatever superimposed
disguises they may wear; the butterfly’s wing, at the present stage of its de-
velopment, seems almost rather to be a mask which is also used for action.
No doubt, however, butterflies are also protectively served in a still more
direct and simple way by the disproportionate bigness of their wings—namely,
by the actual elusiveness to winged insectivores which their consequent tor-
tuosity. and jerkiness of flight insures them. Watch a bird chasing a flying
butterfly (which, by the way, is a decidedly uncommon happening—as if
birds had learned the futility of such chases), and you will see how great is
the butterfly’s advantage, in spite of his offering a far broader target, over
the ‘‘wheeling”’ beetle or even the swift, straight-flying bee. His body bobs
up and down between his wings, and his wings carry him in a crazy, zigzag
course—baffling, as a rule, to the most adroit ‘dodgers’ among birds. .

Among the butterflies whose big, picture-patterned wings have in addi-
tion highly diversified contours, familiar examples are those of the genera
Grapta and Vanessa, etc., often called ‘“‘Angle wings,’ and the ‘“swallow-
tailed” Papilionide.

II. Moths

There are also many long-“‘tailed” moths, like the great pale-leaf-green
Luna (Actias luna) of North America, and the beautiful, diurnal, butterfly-
like Urania moths of South America, etc. These Uranias are not only diur-
nal, but preéminently aérial, spending the daylight hours largely in swift
and tireless flight above and through the forests. They are marked—rather

232

more minutely than one would expect them to be—with black, or dark
shadow-brown, and iridescent green-blue, green, or golden bronze. Judg-
ing by the fineness of their rich obliterative patterns, as well as their pro-
nounced appendages, the “‘tails” on their hind. wings, we must suppose these
moths to have habits of quiet diurnal resting or feeding, of which we know
little or nothing. But the “tails” of some of them, e. g., the most beautiful
Urania leilus (called in Trinidad the ““Green Page”), undoubtedly serve
them in flight, in the manner of the tails of peacocks and pheasants, etc.
(Chapter XVII, p. 95)—leading enemies to strike behind them. For these
tails are white (brightest at the tip, and forward blended into green), and the
most conspicuous part of the moth in flight. Like the tails of certain newts
and lizards (which also, as we have seen, are often thus ‘dazzlingly’ and
‘distractively’ colored), these white appendages can even be seized and torn
off without grave injury to their possessor, who thereafter merely wants one
safeguard. Doubtless, however, they often cause the attacker to strike en-
tirely behind the moth. A like use, among others, is evidently subserved by
all rear-end appendages of moths and butterflies—especially aérial ones, and
especially when the appendages are very light colored, or transversely marked.
Indeed, the same service is no doubt rendered even by the light- or bright-
colored hind wings foiled by dull fore-wings, so very common among moths,
although other effects of this combination are probably of more importance.
It constitutes, for instance, a true ‘eclipsable dazzling costume,’ exactly
corresponding to that of many butterflies. For as the butterfly, alighting,
hides the dazzling-color of its upper side by folding its wings perpendicularly,
so the moth alighting hides the dazzling-color of the upper side of its hind
wings by folding its fore-wings flatly over them. Yet even this is probably
only a subsidiary function of such markings of moths. If they catch the eye
when the moth is flying, they will abet his ‘vanishment’ when he alights by
their total and abrupt eclipse. Yet their main tendency is probably the
reduction of their wearer’s conspicuousness in flight. They are, in fact, oblit-
erative flight-patterns, like those worn by aérial butterflies. If a creature is

233

to fly amid surroundings much and brightly variegated, he will be the less
conspicuous the more bold samples of his environment’s varied spots and
colors he bears on his own surface. Such an enrichment of attire for greater
average inconspicuousness in flight has Nature furnished many moths, on
the hind wings. When, as is common enough, these are mainly whitish, or
of some very pale color, they serve a still more definite obliterative purpose,
and that by night as well as, or rather better than, by day. Like the white
sterns of ruminants and hares, the white back-patterns of grubbing nocturnal
carnivores, etc., they often nearly or quite match the sky. Thus a white- or
pale-hind-winged moth retreating in free air, especially at night, will often
be quite undistinguishable against the sky, while one with dark hind wings
would be plainly visible. But many have dark hind wings, or hind wings
with strong dark markings, and such a coloration seems meant for daylight
rather than for night-light use. Indeed, though most moths are almost
wholly nocturnal, their costumes, with few exceptions, are doubtless specially
adapted to diurnal use, For most of them pass the day in the open air, sitting
motionless, flatly folded, on tree trunks, rocks, grass blades, dead or living
leaves, or the brown, leaf-strewn forest ground. It is chiefly against dis-
covery by daylight in such-like situations that the intensely high-wrought
“cryptic” coloration of their upper sides avails them; as the often far simpler,
brighter, and more boldly variegated coloration of the hind wings, wholly
hidden while they are perching, avails them when, disturbed, they are forced
to make a daylight flight.

But the special forte of moths’ coloration lies in their finely wrought hid-
ing- patterns, which, for specialization and variety, for marvelous minuteness
and obliterative potency, are not to be surpassed and scarcely even to be
equaled in any other branch of the entire animal kingdom. These patterns
differ from the corresponding ones of butterflies (all but the few flatly-applied
kinds, like the South American and West Indian ‘“‘Creaker” (A geronia fer-
onia, etc.), whose bark- and lichen-pattern is almost as exquisitely and mi-
nutely wrought as that of any moth), just as their wearers differ from the

234

Fia. 134. Two grass-moths. (Dead
grass.) Compare Fig. 135.
Photographed from nature (dead moths.)

Fig. 185. Tiger-moth on sprig of box. Compare with Fig. 134.
Photographed from life by Cherry and Richard Kearton. Courtesy Cassell and Co.

Fic. 138.

Bark-moths of the finely-grizzled type. Fig. 136, four on maple bark. Fig, 137, two on pitch pine, Fig, 138, three on gray birch.

butterflies in habits. They are far more fixed and still, in their daylight
perching, and they sit flatly applied to their perches, instead of standing out
from them perpendicularly. Thus they are fit subjects not only for higher
particularization and greater minuteness of pattern, but for direct, near, flat-
surface-picturing costumes, from which the element of perspective-picturing
is largely excluded. Naturally, this rule has exceptions. There are ground-
perching moths—grass moths—for instance, covered with representations like
the Rocky Mountain Ptarmigan’s (Figs. 40 and 41 of Chapter VII), of dry
grass blades crisscrossing over a background of shadow. Such a moth is
shown in Fig. 134, A. Perching among slender grasses some inches above
the earth, a moth like this has often a background full of diverse distances,
of little ‘vistas’—and it is patterned accordingly. This, indeed, is not an
uncommon type of coloration among moths, and there are many variations
on it. Kindred pattern-schemes occur also among woodland moths—both
terrestrial ones, which perch on fallen dead leaves, and those that are wont
to sit in trees, on green or withered foliage still unfallen. (See Fig. 135.)
But the vast majority of moths habitually sit pressed close against a flat or
flattish surface, which wholly hides their undersides, and prevents their hav-
ing any more distant background, except in extreme side view. The aspect
of this flat surface is pictured on the shielding upper sides of the moth’s
fore-wings, and on its head and thorax,—or, in the case of species which sit fully
outspread, on both fore and hind wings, and the entire upper surface of the
body,—often with an almost microscopic particularity of detail. Only the
slightest reduction from the real size of the imitated details is needed in this
picture-pattern, for the space between picture and model is almost nil. In-
deed, though we may pretty safely assume, in view of Nature’s prodigal per-
fectionism, that the moth’s pattern is thus as it were ‘focused’ for the very
closest average unison with its background, the difference and its adjustment
are often too slight for man’s eyes to recognize with certainty. But there
can be no doubt that the coloration. of these flatly-applied moths is on the
whole obliterative rather than mimetic; that, in other words, such a moth

235

characteristically seems merged into the flat plane on which it sits, rather
than showing its real, slightly raised form and passing for an inanimate excres-
cence. Of course, however, this rule has exceptions. Any such moth must
sometimes, especially in side view, present and profit by the mimetic instead
of the obliterative aspect; and there may be some moth-costumes which have
been developed for full and elaborate mimicry of this kind, at the expense of
‘obliteration.’ But that this is exceptional* is amply shown not only by the
character of most moths’ patterns, but by the complete obliterative shading
which their usually plump bodies bear. This can be seen to best advantage
on the very large-bodied kinds, notably the hawk moths (Sphingide); but
—supposititious mimetic moths aside—there are almost no species that lack
it. Usually the bodies are not only counter shaded, but marked with oblit-
erative patterns—either such, already mentioned, as codperate with the back-
ground-pictures on the wings, or bolder ‘secant’ and ‘ruptive’ patterns which
tend to obliterate the bodies in side view, when exposed to sight below the
wings. A similar service is rendered by the more or less abortive patterns
of the under sides of the wings, which are usually dim and imperfect counter-
parts of those of the upper sides. In most cases, they are normally quite
hidden while the moth is perching, and their frequent comparative crudeness
seems therefore to be in just proportion to the smallness of their use. In
flight they are of course exposed—though much less clearly than the upper-side
patterns, because masked by shadow—and they then, especially in the cases of
the brighter and bolder ones, have a distinct share of obliterative effect. On
the other hand, the prevalent paleness of the under sides of the wings must be
classed with obliterative counter shading. But the pattern of this part of a
moth is evidently of scant importance, and accordingly tends to be scantily
developed, compared with the upper-side pattern, and with the under-side
patterns of perpendicularly-folding butterflies.

There are, indeed, perpendicularly-folding moths, just as there are flatly
applied butterflies, and the types of pattern are correspondingly interchanged.
* (If there be such cases)—A. H. T.

236

Fre, 140, Isolated
bits of the same moth,
intermingled with
bits of the surround-
ing birch bark.

Fie, 139, Sphinx Moth (Philampelus pandorus) on a birch trunk.
Photographed from life by Dr. R. W. Shufeldt,

But—especially in the moths’ case—these are rare exceptions to a widely com-
prehensive rule. On the other hand, moths’ regular habit of flat-folding is sub-
ject to several notable modifications. Many small kinds fold up almost cylin-
drically, ‘furling’ their wings around their bodies, and when thus folded they
sit fitted close to slender twigs or grass blades—like certain tree toads. Such
moths often bear a mimetic likeness to bits of stick or grass, or even to bird-
droppings, but often also they are patterned and colored obliteratively. Again,
the triangularly folded wings of many tree-bark moths, etc., slope downward
steeply from the top ridge of the thick body, so that the moths’ picture-patterned
surface is by no means actually flat.

Let us glance at a few more special types of pattern characteristic of ‘close-
lying’ moths in general. Among all the various perches which these moths
frequent, few or none are so abundantly favored by them as tree trunks.
Accordingly, the tree-bark pattern, in various forms, is probably the most
prevalent of all picture-patterns.on moths’ wings. The two extremes of this
form of marking are: first, a pattern of the finest grizzling and speckling,
which counterfeits with exquisite minuteness the look of finely broken bark,
flecked with tiny lichens, etc. (see Figs. 136-138), and second, a pattern which
depicts the larger details of rough or ragged bark, rendering, by contrasts of
dark and light, by sharp lines and soft blendings, the look of sharp-edged
substances casting shadows on their background. Each of these types, as is
almost needless to say, is subject to multitudinous variations, and the two
extremes are combined and intergraded to the last degree. A beautiful
example of the larger-detail type, pure and simple, is the sphinx moth shown
in Fig. 139. (See also Fig. 140.) But there are some still further specialized
cases of bark-picturing among moths, sometimes accompanied by highly
specialized habits. A large gray noctuid moth which I saw in the woods of
Trinidad, B. W. I., always perched sideways on the trunks of trees and bushes.
That is, it would sit with flatly-applied wings trending up and down the trunk
instead of across it. Its flight was swift and straightforward, but in alighting
it always whipped itself around into the sidewise posture. The reason, or at

237

least a most significant accompaniment, of this peculiar habit, was not far to
seek. The ‘secant’ stripe, crossing the insect transversely from fore-wing
tip to fore-wing tip (a type of marking very common among moths, whose
patterns, like those of butterflies, are built on the simple basic laws of ‘ oblit-
eration’), was on this kind specialized into a wonderfully sharp and vivid
picture of a vertical bark-ridge. Such picturing of outstanding substance and
cast shadow plays a large part in the disguisement of many animals of many
classes,—nor is it, among moths, confined to those that perch on tree trunks.
It reaches equally high and various development among the ground-perching
kinds. These—the sylvan ones at least—tend to be brown (as the perchers
on tree trunks tend to be gray). Their general scheme of color and pattern
is much like that of the sylvan terrestrial butterflies, but they sit, for the most
part, flatly applied, instead of perpendicularly folded, and therefore need
still more direct and simple ground-picturing patterns. Sometimes, indeed,
they present a resemblance hardly other than mimetic to single, brown, dead
leaves. No doubt there are even full-blown brown-leaf mimics among
them, as there are probably green-leaf mimics among those that perch on
live foliage. But in the main, their coloration is obliterative, not mimetic—
if anything, more patently so than the corresponding coloration of the bark-
perchers. The leaf-strewn forest floor is more uneven, more studded with
projections and pitted with depressions, than are tree trunks, and though a
moth sits flatly outspread on it, his background tends to be less evenly and
plainly near than is the bark moth’s. And, though the ground moths’ ‘“‘cryp-
tic” patterns contain less of the element of diverse-distance picturing than do
those of the perpendicularly-folding butterflies which haunt like situations,
the essential differences between the disguises of these two lepidopterous
types are comparatively small, and sometimes quite in abeyance. Again,
there is even close likeness between the patterns of some of these moths and
that of certain terrestrial snakes, such as the Copperhead (Plate XI). Both
picture dead, prostrate leaves, with their light, sharp edges and blurred shad-
ows. For pure and subtile realism, the background-pictures worn by some
238

of these larger leaf-moths are hardly to be matched in any other branch of the
animal kingdom. (See Fig. 133, B, B and C.)

In the disguisement of butterflies and moths alike there is one seeming
flaw, perhaps supported by insuperable organic limitations. That is, their
usually perfect dual symmetry in all details of pattern.* The markings of the
two wings on one side are as a rule almost exactly duplicated by those of the
opposite pair; and such duality and repetition tends to attract the notice of
the seeking eye. Of course it is only when the wings are outspread that this
duality becomes in any degree a defect. Upfolded, a butterfly, though still
dually symmetrical in fact, is not so in effect, any more than a bird or mammal
is, for only one side can be seen at a time. Indeed, even when a moth or
butterfly is outspread, its duality is usually frustrated in effect simply by the
irregularity of its position relative to the eye. Birds, on the other hand, which
tip and twist their heads, peeping and prying, with eyes in all sorts of irregular
positions, must often see moths and butterflies symmetrical where we should
not. Among moths this duality is often masked by sharp stripes which cross
continuously the whole extent of the expanded or triangularly part-folded
wings. Such a stripe, with its two sides unlike, ‘cuts’ the moth into two
very unequal parts, dividing it across the direction of its dual symmetry, while
the ‘secant’ itself pictures some landscape-detail—a stick or bark-ridge or
leaf-stem, with a shadow on one side of it. Sometimes a marking of this kind
cuts the fore-wings (or, more rarely, the hind wings) longitudinally, either
crossing or skipping the intervening body; but as a rule it is diagonal, forming
one clearly continuous (though not always straight) ‘secant’ stripe when the
wings are folded in the normal resting-posture. There are many wearers
and manifold variations of this marking, which, though often so very simple,
is one of the most potent of the fundamentally ‘obliterative’ details of lepidop-
terous pattern.

It takes the eye of.an artist, as we have said before, to recognize the wonder-

* Of course, both sides of the insect need, in the long run, just the same pattern; while a score
of circumstances tend to rescue it from betraying its actual duality —A. H. T.

239

ful truthfulness of all these pictures which Nature paints. They are all—
whether of bird, beast, fish, snake, or butterfly—not mere approximations,
but essentially and typically true. (The reader must excuse the repetition
of formulas and phrases calculated to bring home to him a vital but most
subtile and illusive truth.) There is sense in the seeming paradox that a
good caricature portrait of a man looks more like the man than he does him-
self; and there is far more sense in the equally paradoxical sounding statement
that the background-pictures worn by animals exceed their subjects in veri-
similitude. For these pictures are not only somewhat caricatured, they are
at the same time epitomized, compounded. Caricature of the average—a seeming
contradiction in terms—is a phrase that fits the case. The salient and essential
attributes of the pictured scenes have been slightly exaggerated, and cleared
of all that is uncharacteristic. Many scenes have been merged into one, but
all have yielded only what is typical and essential. A leaf is a leaf, and has
nothing to lose by looking ordinarily leaf-like and no more, but a moth is
not a leaf, and, if it is to profit by passing for one, it has much to gain by look-
ing extraordinarily leaf-like—for so will the marauder’s eye, seeking it as a
moth, be the more surely balked from detecting it. Intensified qualities
of pure leaf-like-ness of aspect no marauder will easily learn to associate with
something which is wholly foreign to leaves in its real nature.

All this being so, is it any wonder that artists should feel keen delight in
looking at the disguising-patterns worn by animals? They are, in the best
sense of the word, triumphs of art; and in a sense they are absolute, as human
art can never be. He who would learn the surely typical ‘color- and pattern-
scheme of a particular kind or detail of natural landscape—tree-bark, leaf-
strewn ground, or what-not—has only to look at the disguising-costume of the
moth or snake or bird or butterfly which habitually has such a background.
There he will find it in epitome, painted and perfected by Nature herself.
Color and pattern, line and shading,—all are true beyond the power of man to
imitate, or even fully to discern.

240

APPENDIX A

(Professor E. B. Poulton has kindly given us permission to append the follow-
ing very remarkable addition to our subject.)

[Extracts from] A few Notes on South African Chameleons, &c. By G. B.
LonestaFF, D.M., M.A., of New College, Oxford, and Epwarp B.
Poutton, D.Sc., M.A., F.R.S., Hope Professor of Zoology in the Uni-
versity of Oxford, and Fellow of Jesus College, Oxford.*

THE following observations were made during the visit of the British
Association to South Africa in 1905. The conditions were not favourable to
continuous investigation: nevertheless, I believe that some of these scattered
notes are not without interest, especially those referring to the automatic
adjustable countergrading of shadow on the two sides of the chameleon. It
is probable that the independent control of the colours of the two sides of the
body has been often observed before, but, so far as I am aware, this is the
first attempt to explain the significance of the power. The illuminating
effect of a great hypothesis like that of Mr. Abbott H. Thayer’s in the realm
of protective coloration is well seen in the fact that Dr. Longstaff, Professor
C. V. Boys, and the present writer independently grasped the meaning of the
colour-change the moment it took place before their eyes. I do not know
whether my two friends have studied Mr. Thayer’s writings or examined his
beautiful models at London, Oxford, or Cambridge,t but I have no doubt that
it is the result of his work that interpretation was “‘in the air.”

I have to thank Mr. G. A. Boulenger, F.R.S., for kindly naming the
specimens upon which the following observations were made.—E. B. P.

* (Read 7th March, 1907.) [Printed in the Linnean Society’s Journal—Zoology, Vol. XXX,
October, 1907.]
+ [I was familiar with Mr. Thayer’s models.—G. B. L., July 17, 1907.]
241

3. Note on CHAMELEON PUMILUS, Daudin, 9. By Dr. G. B. Loncstarr.

Taken on a shrub, about four feet from ground, in the Botanical Gardens,
Cape Town, oth August, 1905.

Description.—Apple-green; at the back of the eye two patches of greyish-
pink placed vertically; a lateral stripe of the same colour extending from
shoulder to pelvis, widest in middle, where are two dark grey spots. Several
orange tubercles on the back. Belly striped with greenish white; underside
of head striped blue-green and pink. The ground varies to dusky green.

Kept in confinement. Observations on same made at Durban, 16th Aug.,
1905. After it had been kept for some time in the dark it became of the
brightest apple-green. On exposure to light it darkened. Placed on a dark
“‘uniform-case” near the window in bright light it darkened along the dorsal
area.

Taken out into the garden and placed alternately on a black pair of
trowsers and on a white towel. It darkened in both cases, but there was no
noticeable difference. Then put on a twig of a shrub with bright green
leaves it became paler. The side away from the sun was of the brightest
apple-green, the outer side (towards the sun) was darker along the back. The
bright green harmonized wonderfully with the young leaves, the creature
appeared flat, and was scarcely distinguishable. The neck and belly did not
appear to change colour. * * *

4. By Professor E. B. PouLton.

* * * Good fortune gave me as companions in the same compartment of
the train two physicist friends, Captain Creak, F.R.S., and Professor C. V.
Boys, F.R.S. One day, when C. pumilus was resting on the compartment
table, with the long axis of its body parallel to the window, Professor Boys,
who was certainly intended for a naturalist, pointed out that the strongly illumi-
nated side, next to the window, was dark green, while the side in deep shadow,

242

away from the light, was of the brightest tint. The same relationship between
the illuminated and the unilluminated side was seen on many occasions.

This appears to be a most interesting adaptation—a dynamic manifestation
—of the principle discovered in its static form by Mr. Abbott H. Thayer. Mr.
Thayer first suggested that the relative shades of the dark back, lighter sides,
and white under sides of animals were such as just to counterbalance the
diminution of natural illumination from an open sky as we pass from the
back down the sides to the under surface; that the object of this counter-
grading was to neutralise the shadow which would otherwise render the
animal conspicuous. C. pumilus, as I have said, manifests the same principle
in a dynamic form. The side that happens to be turned away from the
light is brightened sufficiently to neutralise the shadow; the high illumination
of the other side is toned down by darkening, the effect being that all appear-
ance of solidity is dissipated. This result must be of great importance to so
large and so defenceless an animal as the chameleon. But for this adjustable
countergrading, the varying degrees of illumination on the side and dorsal
slope turned towards the light, combined with the strong shadow on the other
side, would cause it to stand out among the leaves as an object of conspicuous
solidity and thickness.

243

APPENDIX B

ADDITIONAL NOTES BY A. H. THAYER

CONSISTING OF OBSERVATIONS MADE TOO LATE TO BE EMBODIED IN
THE TEXT OF THE BOOK

Durinc the progress of this book I have been discovering another
beautiful fact about iridescence—one that was, of course, to be expected.
The beautiful colors which compose it, and which leap into existence with
the changing position of the wearer, or of the beholder, are evidently not
mere general attempts at obliteration of the wearer, but are, each, so many
perject color-notes of that background which the changed situation demands.

We have already shown that the peacock’s neck is often leaf-green when
looked down at, and pure blue sky-color when looked u at, so that it tends
to fit itself exactly to each new background. It is now evident that other
animals’ iridescences are, like those of the peacock, repertories of exact back-
ground colors. The gloss of the magpie’s wing is at one moment a glimpse
of sunlit evergreen, while the next instant it is the blue snow-shadow beyond
the tree. In this way this very snow-picture, so perfectly achieved on the jays
by dead color, is reached with equal precision on the magpie by one leap
of iridescence. Throughout the world of brilliant animals, we find iri-
descence playing this same part. The cormorant’s green gloss in the water,
looked up at from deeper down, proves to be a perfect match for the trans-
lucent water itself. The crow’s rainbow sheens, so little thought of as con-
cealers, turn him into such true distance-colors as he sits on the nest, as to
rank him at this moment almost with the grouse for. indistinguishability.
(The nest itself, of course, has the disadvantage of attracting the eye, and
thereby subjecting the occupant to a far keener scrutiny than the grouse

244

has to fear. Since crows are apparently too unappetizing, as well as per-
haps too formidable, to be much bothered by predatory animals, it would
seem to be the eggs, and not the parents, that here most need protection.)

What we know of the concealing-function of such costumes as that of the
black-and-red South American Heliconii will bear further elucidating.
These insects, in their abundance, and consequent general conspicuousness as
a species, are on a par with our common yellow butterfly * here in the North.
Both these species, existing in such immense numbers as to be almost con-
stantly in sight, record, on the beholder’s mind, one cumulative impression of
conspicuousness. Yet each is colored for the utmost average concealment,
at the very time when it most needs it—its feeding time. Such species are
merely further proof of what our book demonstrates, viz., that Nature, in
carrying out her principle of coloring animals for their most trying circum-
stances, sometimes finds herself giving to a species that has one particularly
dangerous habit, a coloration which, while it is the utmost imaginable con-
cealer in the special situation it fits, looks necessarily more or less conspicuous
and out of place everywhere else.

These brilliant Heliconii, so magically concealed by their colors while they
are feeding among red, yellow, or orange flowers, seem to be greatly indebted,
during the rest of their day, to the protecting power of their habit of threading,
with their rather slow flight, the interstices of dense foliage, where fly-catching
birds have but a poor chance to capture them. In this habit of haunting the
dense foliage, as well as in their colors, these Heliconii remind one of Scarlet
Tanagers—a fact worthy of notice.

There is no need of going to the tropics to study the concealing-power of
the coloration of one of these red-and-black or yellow-and-black Heliconii.
Place a dead one, or even an artificial one, on any kind of plant that has
either red, yellow, or orange flowers, and not only. will you find it wonderfully
concealed, but you will perceive that the principle on which this concealment
is achieved would always be operant wherever such a butterfly sat among
such flowers. *Colyas.

245

One word more about Scarlet Tanagers. Their coloration, dividing them
as it does into two things, a red thing and a black thing, is clear proof that con-
spicuousness is not what is aimed at. Were these birds meant to be con-
spicuous, they would, all the more because of inhabiting dense foliage, be
monochrome. (The principle which underlies this fact is illustrated by the
diagrams of letters in Plate V.)

The rule seems to hold good that since animals must first of all breed, feed,
and drink, their costumes will prove to be pictures of the scenes of these oper-
ations. To speak here only of the feeding (the thing that occupies far the
largest part, for instance of a male bird’s time), there is among birds every
degree of peculiarity of feeding-situation, from that of the hawk, which is
the least peculiar—being wherever, in all outdoors, he gets a sufficiently good
chance at a victim—to that of the macaw, which is one of the most peculiar
and unvarying, commonly some tree-top full of luscious fruit, where he has
merely to climb about a few feet to sate himself. What more powerful in-
fluence toward dangerous relaxation of vigilance could be imagined? What
wonder, then, since the macaw’s banquet-hall is forever hung with one gor-
geous tapestry of fruit and foliage scenes with sky-glimpses between, that his
costume proves to be such as marvellously dissolves him into the scene, as he
climbs about, burying his head in cluster after cluster of the brilliant fruit?
This was just as much to be expected as that the hawk, whose feats take place
now in one situation, now in another, should wear the very most generalized
of concealment costumes. .

UPPER-SIDE WHITE PATCHES, ETC.

It is perhaps possible to show still more clearly than we have yet pointed
out the paramount function of upper-side white patches in general.

In imitating, as we have shown that they do, sky-glimpses through inter-
stices of the foliage-background, they pass off those parts of their wearer which
they cover, for spaces,—more emphatically than spots of any other color could.
The reason of this is that sky, the element which they represent, is the very

246 .

essence of distance. All other colors seen amidst the foliage might represent
one or another of its details, and any one of them occurring on an inhabitant
helps to conceal him; but the finishing touch is given by his wearing, generally
on his very middle, this picture of sky, which, because sky of course is not im
the wood at all, but immeasurably far beyond it, here represents no thing
whatever, but an actual hole. When we say, ‘“‘I can see daylight right through
the place,’’ we imply that there is nothing in that direction between our eyes
and space. A white patch, then, in any such situation, whenever the light
falls upon it sufficiently strongly, says clearly to the beholder, “There is
nothing in this direction.” No wonder that such a vast number of species
that have sky glimpses in their foliage-background wear in their costumes
this magical safeguard. Even in dark woods where white itself is much
darkened, and where actual sky-glimpses are few, it is still the prerogative of
these white patterns to represent, and more or less to match, the lightest, most
illuminated and sky-like portions of the background. In general, the credit
of white as an unmistakable glimpse of sky through the trees is so good
that imitations of it easily profit by its name. There are often in sight a
thousand real sky-vistas—how shall a hawk or other animal spend its energy
in guarding against the occasional counterfeit! The fact undoubtedly is,
that disguise, by all the means that we have pointed out, proves so successful
as to discourage investigation, causing it to better repay predatory animals
to watch merely for motion, and waste little effort in scrutiny of motionless
details.

Since the whole panorama of out-door objects is just one complexity of
millions of outlines made by different-colored objects relieving one against
another, each one showing against a more distant one, it follows that amidst
this vast embroidery, a scrap of imitation of it must generally pass unnoticed,
unless it takes the liberty of moving about! All the patterns and ornaments
of the animal world are such scraps of imitation scenery, and their wearers
are hunted both by man and by beast in the same way—viz., the watching
with a relaxed eye as large a tract as possible for the least hint of motion.

247

Habitually to scrutinize the scene point by point would change an Accipiter’s
or a Flycatcher’s life from a sufficiently easy to a most difficult one, such as
would bring him near the starvation point, since he would necessarily bestow
a large amount of his time in searching the wrong place, while his eyes no
longer commanded the whole scene. The very position of Hawks’ and Fly-
catcher’s eyes seems to prove all this to be true, since they face one eye to the
left and one to the right, and therefore commonly regard two different scenes.
No one can suppose that such a bird performs a feat of intellect beyond even
a man’s power, and acutely examines with focused eyes two points at once.
An Owl’s eyes, on the contrary, not constituting his stand-by sense, but needed
at the grabbing-moment, face forward. Also, most interesting to record, the
Hawk’s eyes, not to be wanting in any service, turn forward, and assume
the position of those of the Ow] whenever the occasion demands.

The fact that every pattern in the forest scene is caused by a thing of one
color outlining against things of a different color beyond, makes it inevitable
that similarly-colored notes on the coats of animals amidst the scene should
receive a similar interpretation, and repeatedly pass off one or the other part
of the wearer for something more distant than the rest of him, thus conceal-
ing his existence. Hunters and collectors will find that these explanations
show why they see so few of the inhabitants of the field or forest until they have
once flushed them. Up to that moment each bright detail of these animals’
costumes has commonly passed for a glimpse of something nearer or further
than the thing represented by the rest of their colors.

The longer one studies the subject of concealing-colors, the greater the part
one discovers to be played by the intrinsic obliterative power of strongly con-
trasting patterns. This principle is shown by Figs. 104-106 in our book, but
should have received much more varied and elaborate illustration. We are
forced, now, to leave the reader to make his own further illustrations. Let
him cut out of very dark paper or cloth (cloth is best because is shows no light
edge) some shape,—like, for instance, that of a butterfly—and pin it, smooth
and flat, upon a smooth expanse of cloth of some very slightly darker color.

248

Then, while he looks at this figure from nearly as far off as he can distinguish
it from its background, let some one place a bit of bright white paper, likewise
smooth and flat, in the middle of the end part of one of the butterfly’s wings.
(The white spot should be about one third the wing’s diameter.) The wing
so treated, if it was very dimly distinguishable before, will now prove wholly
invisible, in the vicinity of the white spot. This beautiful principle is of course
a constant factor in the effect of all animals’ patterns,—snakes, wasps, butter-
flies, birds, etc.—and, in the sense that counter shading. merely prepares
animals’ bodies, as it were, to be painted upon, this other principle is almost the
leading one of all. Such a butterfly as Heliconius amaryllis is a fine example.
Against the dark of shadows that nearly match its own dark ground-color,
its red spots ‘obliterate’ its adjacent outlines, and the sharp gold stripe that
crosses the hind wings does the same for that part of the insect. The bright
bar also illustrates the importance of the direction of such marks on animals.
Being continuous (with very slight interruption) right across the insect’s very
body, it not only ‘obliterates’ it as a body, but, by its own conspicuousness,—
in view of the fact that two things can’t occupy the same space,—prevents one’s
suspecting the existence at that point of anything but a yellow grass-stem, or
more often a sunlit twig, further off.

Students once convinced of the real function of all such markings, will be
delighted to discover the wonder-world they constitute.

THE COOPERATION OF INTERPOSED VEGETATION WITH CONCEALING-COLORS

Here is another fact of the greatest importance: Species that live amidst
vegetation are looked at through a certain average amount of interposed foliage
and twiggery.

Let us imagine a man or other predatory animal stationed at some point
in the forest. Obviously there is some limit to the distance to which he can
see through the surrounding thicket, some point beyond which the last inter-
stice is masked by leaves or branches. A little nearer than this limit begins
the distance at which our observer can see, on an average, some small portion

249

of an object. Now from this point to the very space in which the observer
stands there is a graded scale of the average amount of an object’s surface which
would at each particular distance be visible to him. We have learned from
the diagrams in Plate V. that behind such a foliage lace-work any diversifi-
cation of forest colors constitutes a costume more favorable to disguise
than any monochrome. We have every reason to believe that these vegeta-
tion-haunters wear designs absolutely adjusted to codperation with this ever-
present screen.

While a naturalist is observing one Skunk, and conceiving its ruptive
pattern a badge to advertise it, there are at the same moment (or there have
been in the twilight and starlight of the previous night), thousands of other
Skunks absolutely unrecognizable through the disruptive effect of their
bleached-leaf-and shadow-colors seen through the interrupting tracery of
forest under-growth, or of the rank vegetation of the prairie.

ACKNOWLEDGMENTS, ETC.

There are several men not mentioned in our book (written, mainly, several
years ago) whom we should like to thank for generous furtherance, of one sort
or another. Particularly, Alfred Russell Wallace, Sir E. Ray Lankester, and
Mr. R. I. Pocock, in England, and Dr. C. Hart Merriam and Dr. J. A. Allen,
in America. Mr. Pocock, furthermore, as shown by his various essays on
protective coloration, has, independently, an unusually wide grasp on the
whole subject. Had we seen his articles in time, they would of necessity have
modified in some degree the exclusive tone of my Introduction, as well as my
son’s allusions here and there to the comparative apathy and blindness of
naturalists in this matter.

I take this opportunity also to correct, up to the limits of my present
knowledge, several errors which appear in my earlier writings. One of these is
my indorsement of Dr. C. Hart Merriam’s theory about white rear-patches
on deer, hares, etc. (Auk, Vol. XVII, No. 2, April, 1901.) Another is my
avowed belief that there must somewhere be warning colors. (Transactions

250

of the Entomological Society of London, December 24, 1903.) This belief
I no longer hold. Another is my statement, in the same article, that unshiny,
bright monochrome constitutes intrinsically conspicuous coloration. Here I
should have omitted the word bright.

In the same paper, too, I wrote, by a slip of the mind, that animals
have totally different sight from ours. On the contrary, everything that we
know about this matter points to the opposite belief. What I was trying to
say was simply that animals seem to have a different mental attitude toward
their sight, since they appear to detect each other more exclusively than we
do through perceiving each other’s motion.

Lastly, in the same paper, I ascribed more importance to butterflies’ resem-
blance to flowers, as compared to their rendering of scenery, than I now
should. A. H. THAYER.

San Remo, Italy.
December 28, 1908.

LATER NOTES

Our book having spoken of the Scarlet Tanager as often more conspicuous
than dim-colored birds, while we clearly show the concealing-power of red
patterns, I add here the clear distinction which I have at last perceived
between the arrangement of this bird’s red and that of every other species
I have observed. It differs from that of the others in this respect: that while
its contrast with the black of the wings and tail so far produces the usual
ruptive effect, and thus, of course, lessens the bird’s distinguishability, the
red itself occupies continuously his whole head and body, right round him
jrom top to bottom.

This gives these parts the full conspicuousness of un-countershaded mono-
chrome, and to the red itself it gives the peculiar brilliancy that any bright color

251

gains through grading out of shadow into light. This unmistakable conspicu-
ousness of the most vital parts of this bird separates him from all the galli-
naceous birds, from the large rail-class, from trogons, toucans, parrots, macaws,
and a vast number of other species in whose costume brilliant scarlet patterns,
often far larger than an entire tanager, perform demonstrably a totally obliter-
ative part. Of this fact a few moments’ experimenting with even stuffed
specimens of the Red-and-yellow Macaw in a red-apple tree, or of the Quetzal
in summer green-woods, will convince the most incredulous reader. In their
cases, as in those of all the other red-patterned species that I have cited, a red
pattern conceals its wearer in direct ratio to its own brilliancy.

Our two Zebra photographs from Schillings, Figs. 88-89, were included
in the book mainly to prove that Zebras do frequent reeds, etc., at their drinking
times. Obviously, a nocturnal flashlight flaring against their sides and light-
ing so much more feebly the scene behind them, totally prevents their coalescing
with it. The explanation of this disharmony, on page 136, is inadequate.

New figures, one of them presenting the experiment suggested on pages
248-249, have been substituted for the original 104, 105, and 106 of the first
edition. Ay He,

Monavpnock, N. H.,
April, 1910.

252

INDEX

Aard-vark, 126
Ageronia. See Butterflies
“Agouti, 119
Ailuropus melanoleucus, 151
Albatross, 75
Alligator, 154, 176
Amphibians, 178
Anaconda. See Snake
Angler, 167
“‘ Angle-wings.””
Anhinga, 85
Ant, 207
Antbird, 11
Ant-eater, Great Ant-eater, Little Ant-eater,
Tamandua, 126, 149
Antelope ©
common, 142; harnessed, 142; koodoo,
141; Livingstone’s eland, 135, 142; prong-
buck, figure 107, p. 154; figure 108, p. 154;
figure 109, p. 154; figure 110, p. 154.
Ape, 122 5
Aphides, 203
Appendages
crests, note in legend over frontispiece,
obliterative function of, 9, 12, 95; of
butterflies, 224, 230; of moths, 233; pan-
taloons (leg-feathers), 84; plumes, 98,
see legend of Plate VI, opp. p. 107; tails,
95, 108, 233; wattles, 85; wings, 224, 225,

See Butterflies, Grapta

230
Armadillo, 125
Axolotl, 181

Background-picturing Patterns

compounding of, 36; intermingling of
types of, 54; perspective of, 31, 139, 217,
235; realism of, 39, 240; underlying prin-
ciples of obliterative effects of, 30-32, 36,
226-232, 249

Bark Type
beetles, 201; butterflies, 216; cicada, 202;
lizards, 175; moths, 237; spiders, 210;
toads, 179, 180; woodpecker, 50; wry-
neck, .50

Bottom Type
cod, 170; ducks, 63; painted tortoise, 178;
seals, 170; trout, 170

Background-picturing Patterns—Continued

Forest-crown Type
bird of paradise, 109; bluebird, 108; indigo
bunting, 108; jacamar, 109; macaw, 109;
motmot, 109; parrot, 108; tanager, 109;
toucan, Io

Forest-vista Type
Calligo eurylochus, 217; European eagle
owl, 41; great gray (and lapp) owl, 41;
great horned owl, 41; hazel grouse, 38;
ruffed grouse, 38, 39, 40; screech owl, 41;
European woodcock, 42

Grass Type
bittern, 56; curlew, 53; great bustard, 48;
frogs, 46, 180; jaegers, 75; larks, 45;
little bustard, 48; moths, 46, 235; pecto-.
ral sandpiper, 53; pipits, 45; ptarmigan,
45, 46; thickknees, 53; tiger heron, 57;
tinamous, 48; warblers, 45

Ground Type
Calligo butterflies, 218; copperhead snake,
156, 174; frogs, 178; goatsucker, 35, 156;

amchatkan sea-eagle, 152; larks, 44;

locusts, 198; moths, 238; nighthawks,
54, 198; pipit, 45; quail, 45; rattlesnake,
174; skunks, 151; snipe, 33, 34, 156;
sparrow, 45; toads, 181; Thibetan snow
bear, 152; warblers, 45; woodcock, 33,

34
Heather Type
plover, 53; Scotch grouse (Ptarmigan), 47
Leaf Tyee
caterpillars, 186-1
Reed Type ai
antelopes, 141, 142; bittern, 57; herons,
57; zebras, 135-139
Ripple Type
ducks, 62, 92; green heron, 92
Rock Type
butterflies, 216; cormorants, 65; fishes,
165; nighthawk, 54, 165; purple sand-
Piper, 54; seals, 170; spiders, 210
Sand Type -
crabs, 165; curlew, 53; flounders, 164;
knot, 53; locusts, 198; plaice, 164; puff
adder, 175, 198; sanderling, 53; semi-
palmated sandpiper, 53; stint, 53; thick
knees, 53
Shadow Type
spiders, 210; squirrels, 143, 144; tiger, 140;
zebras, 135-138

Background-picturing Patterns—Continued
Sky Type
albatross, 75; ant-eaters, 149; antelopes
153; bald eagle, 74; black lark bunting
157; bobolink, 157; cranes, 154; deer, 152;
egrets, 118, 155; elands, 142; flamingoes,
154; fulmars,75 ;gannets,75; gulls,74,154;
hares,152; herons, 74, 118, 154, 155; ibises,
154; Kamchatkan sea-eagle, 152; larks,
157; longspurs, 157; moths, 234; osprey,
74; ratels, 149; skunks, 148, 151; snowy
owl, 73, 114, 117, 154; spilogale, 150;
spoonbills, 154; storks, 154; swans, 118,
154; Tasmanian devil, 149; terns,154; Thi-
betan snow bear, 152; tropic birds, 75;
white gerfalcon, 114, 154; wolverine, 149;
wood duck, 66, 67, 69; zebras, 138; zoril,

I50
Sun-fleck Type
boa, 135, 175; butterflies, 220, 221; deer,
145, giraffe, 133, 134; jaguar, 133; leopard,
133, 134; mammals, 144; ocelot, 135, 175;
ounce, 135; python, 175; serval, 135;
spiders, 210; wild swine, 145
Water Type
ant-birds, 113; chevrotain, 143; courlan,
61; dragon-flies, 209; ducks, 62, 63;
harnessed antelopes, 142; herons, 58;
jacanas, 59; lape, 143; purple gallinule,
59; rails, 61; seals, 170; wood sandpipers,
I
Winter-landscape Type
blue jay, 114, 115; crossbills, 116, 117;
goshawk, 116; linnets, 116, 117; nut-
hatches, 115, 116; pine grosbeaks, 116,
117; ptarmigans, 113; snow bunting, 116;
snowy owl, 114; titmice, 114, 115; white
gerfalcon, 114; woodpeckers, 114, 115
Badger, 148 -
‘“‘Banner marks,” 5
Bark Patterns. See Background-picturing
Patterns
Bat, 119, 120
Bates, English naturalist, quoted, 224
Beak, 70, 85, 86
Bear, 123, 124, 152
“‘Beauty-spots”’ of hummingbirds, 103, 104
Beaver, 119, 122, 130
Beebe, C. W., on the disguising coloration of
Helicontus charitonia, 221
Beetle, 200
Bill. See Beak
Bird of paradise, 97, 98, 109, see Plate VI, opp.
p. 107
Birds -
aquatic, 59 seq.; arctic, 113 seq.; ground,
33 Seq., 44 Seq.; ocean, 72, 73; scansorial,
“49 Seg.; shore, 52 seq.; swamp, 56 seq.;
tree-perching, 38 seg.; tropical, 107 seq.
Bittern
American, 56, roo, figure 53, p. 58; Eu-
ropean, 57; least, 57

Blackbird
European, 27; red-winged, 86 note

Bluebird, 108

Bobolink, 157

Bob-white, figure 50, p. 48

Borer, 205

Bottom Patterns.

Patterns

Bunting
black lark, 157; indigo, 91, 108; snow,
116, 151

Bustard, 48

Butterflies :
aerial class of, 219-226; dazzling colora-
tion of, 224-232; disproportionately large
wings of, 230; mimicry of, 214, 215, 228;
ocelli of, 229; sedentary class of, 219-226;
symmetry of wings of, 239; wing-waving
of, 219, 245; figures 56-57,.p. 78; figure
106, and figures 128-133.

Ageronia, 234; Calligo, 229; Euchle carda-

mines, 216; Grapta, 232; Hetera esmeralda,
224; Heliconti, So. American, 245; Heli-
conius amaryllis, 249; Heliconius chari-
tonia, 221, 223; Heliconius melpomene
214, 215, 216; Heliconius sara, 223; hum-
mingbird papilio, 223; Hypolymnas mi-
sippus, 221; Kallima wmachis, 4, 214, 216;
Lycorea atergatis, 223; Mechanitis verita-
bilis, 223; Metamorpha dido, 216, 222;
Morpho anaxibia, 225; Nymphalis bolina,
221; Papilio gargasus, 223; Papilio poly-
damas, 220; Papilionide, swallow-tailed,
232; Pierine, 228; Satyrine, 220; Tithorea.
megara, 223; Vanessa, 232

Buzzard, rough-legged, 84

See Background-picturing

Caddis, 209

Calligo. See Butterflies

Camelopard. See Giraffe .

Cape Polecat. See Zoril

Capybara, 130

Cat, 4

Catbird, 27

Caterpillar
see Plate XII, opp. p. 183; Plate XIII,
opp. p. 188; Plate XIV, opp. p. 192; Plate
XV, opp. p. 194; and Plate XVI, opp. p.
196; background-picturing of, 191-193;
co-operation of mimicry and counter-shad-
ing of, 188-191; mimicry of, 193-197;
obliterative shading of, 185 seq.

Chafer, American Rose, 201

Chameleon, dynamic counter-shading of, 242,

243

Chameleonism
of chameleons, 242, 243; of fish, 168: of
frogs, 180, 181; of lizards, 175; of toads,
179

254

Chapman, F. M., on the birds of Trinidad, 111
seq.

Cheetah, 153

Chevrotain, African Water, 143

Chickadee, figure 61, p. 78

Chipmunk, 143, figure 13, p. 28, and figure 93,

p. 138

Cicada, Dowtay, 202

Civet, 119

Cockroach, 200

Cod, 170

Color
of desert animals, 127; of female birds, 39,
70, 78, 106, 117, 145, 148; secondary part
of, in animal distinguishability, 17

Bright

concealing effect of, 4, 19 and note, 86
note, 87-94, 104, 222; of bills and feet of
birds, 85, 86; dimmed by foliage-reflec-
tion, 111; of amphibians, 182; fishes, 165,
166, 168; hummingbirds, 104; lizards, 172;
northern birds, 116; painted tortoise, 177;
trogons, 111; scarlet tanager, 111; snakes,

172
Changeable
kinds of, among birds, 91; ‘window-
opening’ effect of, 93
Complementary
in tropical bird costume, 110, 111
“Cryptic,” 11, 212, 214, 234
See also Iridescence and Chameleonism
Conepatl. See Skunk
Coot, 59, 61
Cormorant, 65, 244
Cougar, 3, 153
Counter-shading
distinguished from obliterative coloration,
25; experimental demonstrations of po-
tency of, 20, 25, 140, 186, 187: inverted,
124, 147-150, 186, 211; law of, 27; solidity-
effacing effect of, 14-16 :
_ See also Obliterative Coloration
Courlan, 61
Crab, aquatic, 165; sand, 156; spirit, 165
“‘Creaker.”” See Butterflies, Ageronia
Creeper, wood, 49, 115
Cricket, 200
Crocodile, 176
Crossbill, 116, 117
Crow, 244
Curlew, 45, 53, figure 76, p. 82

Darwin,-Charles, 11, 12, 16

Dazzling Marks. See Markings

Deer, flight-masks of, 152, 153; obliterative
markings of young of, 145

Desert, coloration of animals of, 26

Dewdrop Patterns. See Patterns

ala Lar importance of slight advantages of,

? iD

Distractive marks.
Dog, 4, 119
Dolehie, 119
Dragon-fly, 207, 209
Duck
eider, 62, 65, 79, figure 47, p. 46; gar-
aney, 62; golden-eyes, 62; harlequin, 78;
ong-tailed, 62; mallard, 89; mandarin,
71; merganser, 62, figure 78, p. 82, and
figure 79, p. 82; old squaw, 62; pintail,
62; ruddy, 64; scaup, 64; scoter, 65; teal,
62; widgeon, 62; wood, 62, 66-71, 92, 130,
177, see Plate III, opp. p. 59, and Plate

V, opp. p. 70
Duck-billed Bidens, 122
Dugmore, A. R., quoted, 168
Dugong, 123

See Markings

Eagle, 74, 152

Earwig, 200

Echidna, 121

Eckstorm, Mrs. F. H., 19 note

Eclipsable Markings. See Markings

Egret, 58, 155, figure 116, p. 156; figure 117, p.
156; figure 118, p. 156; and figure 118 A,

p. 156
Eider. See Duck
Eland. See Antelope
Elephant, 119
Ephemera, 209
Euchle cardamines. See Butterflies
Eyes, masking of, 81, 82 and note

Feathers, in the composition of patterns, 139

Female, sexual differences in costumes of, 27,
39, 60, 65, 70, 71, 78, 105, 106, 117, 145

Ferret, 4

Fish, 160-171

Fisher. See Martin

Fish Hawk. See Hawk, Osprey

Flamingo, see Plate IX, p. 156, and Plate X,
p. 156, and legend; ‘‘showy”’ costumes
of, 154

Flight masks, 152, 153

Flight Patterns. See Patterns

Flounder, 164

Flower Patterns.

Fly, 206

Forest Background Patterns.
ground-picturing Patterns

Fox, 3, 7, 119, 151, 152

Frog, 46, 35. 156, 167, 169, 178, figures 125-126,
p. 180

See Patterns

See Back-

Gadow’s marks, 5
Galadictis, striata, vittata, 147
Gallinule, 59-61, 91, 130

255

Gannet, 155

Garganey. See Duck

Gerfalcon, white, 114, 152

Gila monster, 174

Giraffe, 132-134

Glutton. See Wolverine

Gnat, 207

Goatsucker
mimicry of, 101; minute patterns of, 35,
39; young of, 82

Golden Eye. See Duck

Gopher, 127

Grampus, 123

Grapta, See Butterflies

Grasshopper, 199, 200

Grass Patterns. See Background-picturing

bas po aed ca

tebe, 8 gure 77, Be 82, an ure 80, p. 82

“‘Green Page. See Moths, Urania

Grosbeak, 116, figure 13, p. 28

Ground Patterns. See Background-Picturing

Patterns
Grouse
figure gu ,P- 37; figure 32, p. 37; figure 33,
p. 40; figures 34-35, p. 40; eure 43, P. 443

figure 44, p. 46, and figure 45, p. 46; hazel,
38; ruffed, 38, 39, 40, 69, 100, 101, 156,
217, see Plate II, opp. p. 38; Scotch, 45;
young of, 82

Guillemots, figure 63, p. 78

Gull
coloration of, 72; black-head, 74; jaegers
(robber), 75; laughing, 74; young of, 74,
75, figure 75, p. 82

Hairs, in the composition of patterns, 139
Hare, 7, 119, figure 85, p. 128; figure 86, p. 128;
figure 103, p. 150; figure 112, p. 154; and

figure 113, p. 154
Harlequin. See Duck
Hawk

figure 13, p. 28; prey-bewildering mark-
ings of, 80; wing area of, 231; goshawk,
80, 116, figure 64, p. 80; figure 65, p. 80;
and figure 66, p. 80; harpy 84; osprey, 74,
85; red-tailed,
Heather Patterns.
Patterns
Hedgehog, 119, 121
Heliconit. See Butterflies
Hen, 25, figure 6, p. 26
Heron
coloration of, 58; colored beaks of, 85;
habits of, 56; great lve, 74; green, 92;
urple, 57; tiger, 57; white, 155
H res hy, . a Butterflies
Hiding Patterns. See Patterns
Hippopotamus, 119
Hole-picturing. See Patterns

2
See Background-picturing

Mopper

eaf, 204; tree, 202

Hornet, 205

Hornpout, I

Hanmingbint Papilio. See Butterflies

Hummingbirds
coloration of females, 105; function of
flashing headgear of, 105 note; oblitera-
tive equipment of, 103-106

Hunting Frog. See Angler

Hyena, 119

Hypolymnas misippus.

Hyrax, 119

See Butterflies

Ibis, 154

Iguana, 174

Inchworm, 4

Indistinguishability, conditions of, 7, 9-11, 13

Iridescence
potency of in animal concealment, 87-89,
94, 95, 244, 245; of butterflies, 224; of
dragon-flies, 208; of fishes, 167; of flies,
206; of herons, 58; of humming-birds, 103

Jacamar, 90, 109, 206

Jacana
colored wattles of, 85; habits of, 59;
obliterative shading in young of, 60;
spurs of, 60, 61

Jackal, 127

Jaguar, 132, 133, 134, figure 87, p. 132

Japanese, animal pictures of, 28 note

Jay, blue, 114, 115, see Plate VI, opp. p. 107;

figure 13, p. 28, and figure ‘60, p. 78

Kallima inachis. See Butterflies

Kangaroo, 132

Katydid, 199

Kingfisher
changeable coloration of, 90, 91; dazzling
markings of, 155; habits of, 130; com-
mon European, gl

Kipling, Rudyard, quoted, 135 note

Knot, 53

Koodoo. See Antelope

Lape (Paca), 143

Lapwing, figure 69, p. 81

Lark, 44, 157

Leaf-disease-spots, mimicry of by caterpillars,
189

Leaf insect, 198

Leaf Patterns.
terns

Leaf-vein Patterns.

See Background-picturing Pat-

See Patterns

256

Leg-feathers. See Appendages (pantaloons)

Lemming, 144

Lemur, 144
Leopard, melanism of, 133; pattern of, 134,
figure 17, p. 30

Linnet, redpoll, 106, 116

Lion, 132, 135, 137, 153

Lizard, 172, 174, 175, 233, figure 124, p. 180

Locust, 198, 200

Longspur, 157

Longstaff, G. B., note by, on South African
chameleons, 242

Long-tailed Duck. See Duck

Lustrousness, importance of, as a factor of
obliterative coloration, 148, 226

Lycorea atergatis, See Butterflies

Lynx, 7, 119
M

Macaw, 109, 246
Magpie, 115, 244
Mallard. See Duck
Mammals
absence of bright coloring in, 130; ar-

boreal, coloration of, 129; disguising
coloration of, 119 seq.

Mandarin. See Duck

Manatee, 123

Mantis, 198

Mantispian, 209

Marbling. See Markings

Markings .
axiom of, 80; concealing principles of, 77-

80, 95, 96
Dazzling (Distractive)
principles of, 151, 152, 246, 247; of but-
terflies,.219, 225, 227, 233; gulls, 74; hum-
ming birds, 104, 105; i aha sea-
eagle, 152; locusts, 199; moths, 233;
plunging fishing-birds, 155; ptarmigans,
152; skunks, 151; snowy owl, 151, 152;
terns, 74; Thibetan snow bear, 152; wea-
sels, 152; white gerfalcon, 151, 152
Eclipsable
of butterflies, 227; of deer, 153
Eye-masking, 81 and note, 82
Marbling, 70
Ocelli
disguising effect of, 229, 230, legend of
Frontispiece, figure 132, p. 230
Speculum
effect of iridescence of, in the Mallard, p. 89
function of, in disguise of ducks, 64
Stripes, lengthwise
concealing principle of, 95, 96; of birds,
95, 96; caterpillars, 195; snakes, 10, 96,

174

Stripes, transverse
concealing principle of, 95, 96; of antelope,
135, 141; beetles, 201; hawks, 80; iguanas,
174; lizards, 174; Myrmecobius fasciatus,

Markings—C ontinued
Stripes, transverse—Continued
141; owls, 80; pheasants, 95, 97; quaggas,
141; snakes, 10, 96, 97, 174; tigers, 140;
zebras, 135
“Target,” 97, 182

Marmoset, 144

Martin, Pennant’s (Fisher), 123

Meadow lark, figure 46, p. 46

Mechanitis veritabilis. See Butterflies

Melanism, of the leopard and jaguar, 133, 134

Merganser. See Duck

Merriam, Dr. C. H., 250

Metamorpha Dido. See Butterflies

Mimicry
approach of obliterative coloration to, 36;
““Batesian and Mullerian’’ groups, 223;
color and pattern, 195; compound, 184,
216; codperation of, with obliterative
shading, 188; definition of, 24 and note;
distinguished from obliterative colora-
tion, 100, 101, 103; structural, 193, 194;
of butterflies, 4, 214, 215, 224, 228; cater-
Pillars, 4, 183-197; crocodilians, 176;
dragon-flies, 208; fishes, 167; grass-snake,
173; moths, 4, 236; red crossbills, 117;
sloth, 124; spiders, 210; toads, 179; tree
hopper, 203; woodland goatsucker, rot

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Full text of "Concealing-coloration in the animal kingdom; an exposition of the laws of disguise through color and pattern: being a summary of Abbott H. Thayer's discoveries"

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